: Hot hot hot then not???



Keith Carlson
10-12-10, 04:17 PM
Hello, Iím new to your forum and need some help. My 98 STS has been over heating once to the extent that the car went onto idle mode. I replaced the water pump and thermostat on Sunday and all seemed to be fine so I drove it to work the next day and half way through my 14 mile jaunt the temp needle went to about 2:30 on the dial then back down to itís normal 12:00 position after about a mile. Then on the way home it was fine until I was just about home and it shot up again this time to 3:00 I gingerly drove the last few blocks and shut her done. I had an infrared thermometer that I pointed at several spots on the radiator and got readings of 84-96 degrees. I then pointed it at the upper radiator hose and got 226 degrees. Is this a sign of a clogged radiator? If so how do you flush the system? The car has 140,000 on it and at 90,000 the case halfís were done and the HGís. Any help is greatly appreciated. Thanks!

Submariner409
10-12-10, 04:59 PM
226 is just above the temp where fans go to SLOW (224) with no A/C function set. (Fans go to FAST at 236). The thermostat starts at 188 and is fully open at 206. The 12:00 tick mark is heavily damped so the temp there can be anywhere from 190 to 215. Normal.

The cold radiator sounds like air pockets in the system - have you checked the coolant reservoir purge line - that small hose which runs from the bolt nipple at the water pump cover to the top side of the coolant reservoir ?? That line should show a constant low flow of coolant - it's used to purge air from the system. The hollow bolt nipple is prone to clog with scale. Normal coolant level is halfway up in the reservoir, cold.

Is this your gauge ???

Welcome Aboard !!! :welcome:

Keith Carlson
10-12-10, 05:15 PM
Yep that's the gage, I'll have to check that purge line. Last week when the car got hot enough to go into idle mode I had to put over a gallon of 50/50 in it to bring the level up maybe air got trapped?

Submariner409
10-12-10, 05:41 PM
Yep that's the gage, I'll have to check that purge line. Last week when the car got hot enough to go into idle mode I had to put over a gallon of 50/50 in it to bring the level up maybe air got trapped?

That thermostat and the coolant flow is oddball compared to what you may be used to...............

I think your coolant reservoir has a legend and arrow molded into the side - proper cold fill level should be at about the center tank seam.

Keith Carlson
10-12-10, 08:22 PM
Went out after work and checked the purge line. I ran a good size wire through the inlet to the tank but couldnít till if it was plugged or not, I disconnected the hose and fluid did come steadily through the hose but you could not see anything moving in the tank once hooked up again. I brought it up to temp 12:00 on the gage with the cap off and finally at about 12:30 it started to bubble out of the tank and the car continued to rise in temp so I put the cap back on and it went back to 12:00 normal. When it is at idle the upper hose is soft when you squeeze it until you raise the RPMís then it gets harder, Is that normal?

Keith Carlson
10-12-10, 09:30 PM
Not sure if it’s relevant or not but there is also a semi high pitched whistle coming from the TB area but I was unable to determine it’s origin even probing with a stethoscope.

Submariner409
10-12-10, 10:52 PM
Not sure if itís relevant or not but there is also a semi high pitched whistle coming from the TB area but I was unable to determine itís origin even probing with a stethoscope.

The reservoir/purge line is a low-flow header tank - you'll never see coolant moving in that tank except for the purge line dribble.

Throttlebody whistle ??? - Look for a vacuum leak.

A 50/50 mix of coolant boils at about 220 at atmospheric pressure - your car uses a 16 (maybe 18) psi cap to raise system pressure and therefore the boiling point to about 265 - with the cap off the coolant will boil before the fans come on. Cap-off checks accomplish nothing. With the cap on from cold start the hoses will get rock hard as the engine warms.

(For coolant boil points at pressure, read the label on the back of any coolant jug.)

Keith Carlson
10-13-10, 08:13 AM
When mine warms to normal running temp at idle speed the top hose (when I say top hose it is not the one with the thermostat) does not get hard at all before and after the water pump/thermostat replacement? Only when I bring the RPM’s up does it start to get hard but never rock hard?

Submariner409
10-13-10, 10:10 AM
When mine warms to normal running temp at idle speed the top hose (when I say top hose it is not the one with the thermostat) does not get hard at all before and after the water pump/thermostat replacement? Only when I bring the RPM’s up does it start to get hard but never rock hard?

Hmmmmmmm.....................Instead of idling the engine to warm it up for cooling system checks, start up and go for a 20 minute drive. Drive normally - nothing different. Now stop somewhere and pop the hood - top hose hard ??? Should be. If not, suspect the coolant reservoir cap or the smoothness of the reservoir neck seal surface. Worst case - a cracked reservoir at either the filler neck or purge line nipple areas. Your reservoir cap is a 16 psi unit, I believe - $9 at a NAPA or large parts store - probably made by Stant or Gates.

Keith Carlson
10-15-10, 09:00 AM
Which way does the coolant flow in or out of the thermostat?

Submariner409
10-15-10, 09:54 AM
Which way does the coolant flow in or out of the thermostat?

Post #4 - two pictures with flow direction.

Keith Carlson
10-15-10, 03:56 PM
Pictures didn't show up?

tateos
10-15-10, 04:36 PM
That thermostat and the coolant flow is oddball compared to what you may be used to...............

I think your coolant reservoir has a legend and arrow molded into the side - proper cold fill level should be at about the center tank seam.

Very nice picture of the thermostat with annotations Sub - good job!

Submariner409
10-15-10, 05:13 PM
Pictures didn't show up?

What browser are you using and what are your antivirus and SPAM settings - you may be blocking picture downloads - my 2 (click on the links in Post #4) have been in other threads for years. Try this...............

Submariner409
10-15-10, 05:18 PM
...............and this

Keith Carlson
10-15-10, 05:59 PM
Sorry it didn't clik in my mind to go to post #4 when I saw it I can see them thanks. I'm going to get the car up to temp and remove the upper hose to see if any thing is flowing back into the radiator.

Submariner409
10-15-10, 09:43 PM
Sorry it didn't clik in my mind to go to post #4 when I saw it I can see them thanks. I'm going to get the car up to temp and remove the upper hose to see if any thing is flowing back into the radiator.

If the engine is "up to temp-" and you uncork that upper hose you're in for a really nasty, dangerous surprise. You'll have your hands full of 210-220 degree coolant and can kiss the electric fans and EBTCM goodbye - a mere $2,000 mistake.

Better to go to Radio Shack and spend $15.95 for a small IR spot thermometer: point it at a 1" spot from 4" away and it gives you the temperature of that spot - instantly.

Coolant - pressurized coolant - is nothing to fool with; better safe than sorry.

Keith Carlson
10-16-10, 06:31 PM
Shouldnít the radiator get hot or at least warm to the touch after almost hitting red line on the gage? I just drove the car about 25 miles down the highway and at about 23 miles the gage went almost to the red area. I got off the highway and pulled over at the same time the needle was already coming down closer to normal 12:00, with the car still running I went under the hood and the top hose felt pretty hard but I could put my hand any ware on the front of the radiator and it was cool to the touch?

RippyPartsDept
10-16-10, 07:03 PM
sounds like your radiator is stopped up and the coolant isn't flowing through it ... or your water pump isn't pumping the coolant through the system...
something is keeping the coolant from circulating

Submariner409
10-16-10, 07:08 PM
with the car still running I went under the hood and the top hose felt pretty hard but I could put my hand any ware on the front of the radiator and it was cool to the touch?

You didn't touch the radiator - you placed your hand on the air conditioning condenser - it's another radiator in front of the coolant radiator.

Stick your face down low, near the engine oil dipstick and determine if you can feel hot air blowing from the fans, which should be in FAST if the gauge went to the redline.

Go get the IR thermometer from Radio Shack - stop guessing at "hot" and "cold" and "cool".

RippyPartsDept
10-16-10, 07:39 PM
:yeah: forgot about the condenser... and do get the IR thermometer... takes all the guess work out

Keith Carlson
10-17-10, 11:06 AM
Yep, I forgot about the condenser too. As I stated before I have an IR and will check it next time she gets hot. Going to drive it 20 miles to the fair grounds for a swap meet Iím sure on the way it will get hot again.

Submariner409
10-17-10, 02:31 PM
Yep, I forgot about the condenser too. As I stated before I have an IR and will check it next time she gets hot. Going to drive it 20 miles to the fair grounds for a swap meet I’m sure on the way it will get hot again.

IF it overheats (gets past the 1:15 tick), you want to "shoot" the metal just at where the top radiator hose connects to the engine: that gives you block temp. Then shoot the water pump cover/thermostat housing where the heater return hose connects: that will give you heater circuit temp (Post #15 diagram).

Keith Carlson
10-17-10, 03:05 PM
I’m begging to think I maybe getting false readings. After 14 miles the needle once again came close to the red area. I pulled off the highway and it began to go done again. I pointed at the inside by the fans with the IR and got readings of 195 the hose connection was 204 as with the waterpump cover. I was able to take the cap off and the coolant was 195 but of course the needle was back to 12:oo by this time. I’m not loosing any coolant it as full now as before.

maeng9981
10-17-10, 05:41 PM
For some reason, the temperature of the upper hose surface doesn't give you a correct temperature. Mine indicated 188 when my temp gauge was at 6/8 mark.

Pointed at the area between water pump and thermostat and it read 229.

Submariner409
10-17-10, 09:10 PM
For some reason, the temperature of the upper hose surface doesn't give you a correct temperature. Mine indicated 188 when my temp gauge was at 6/8 mark.

Pointed at the area between water pump and thermostat and it read 229.

Braid reinforced rubber hoses are essentially insulated. Always take temps at the metal nipples and connectors, as posted.

Keith Carlson
10-18-10, 07:59 PM
I drove the car to work today with no issues. On the way home the gage went to about 2:00 and within about 20 seconds it was back to normal, it did this twice.
It is obviously not over heating because there is no way it could go back to normal temp that quickly. Must have a bad temperature sending unit?

maeng9981
10-19-10, 01:17 AM
Must have a bad temperature sending unit?

...or air in the cooling system.

Keith Carlson
10-19-10, 10:08 AM
Drove to work again and almost hit red line but went back down again quickly. This time the heater was on and the air went cool until it went back to 12:00 then the heat came back. Now I believe that’s a sign of over heating. How do you get the air out of the system. I’ve heard you have to burp the system but how do you do it?

Submariner409
10-19-10, 11:45 AM
Drove to work again and almost hit red line but went back down again quickly. This time the heater was on and the air went cool until it went back to 12:00 then the heat came back. Now I believe that’s a sign of over heating. How do you get the air out of the system. I’ve heard you have to burp the system but how do you do it?

Down near the water pump/thermostat cover there's a bolt-nipple with a 5/8" hose attached - that hose runs to a nipple at the top side of the coolant reservoir (NOT a coolant overflow hose which you may or may not have - that hangs down from the cap out the bottom of the car). The hose is called "purge line" and it automatically, 24/7, bleeds air and gases out of the system into the airspace over the coolant in the reservoir. Sometimes it or one of the nipples clog up.

With the engine cold, open the reservoir, disconnect the hose from the tank nipple and hold it in the open filler neck. Have an assistant normally start the engine - a few spits then a steady stream of coolant should flow. If not, then you need to find and clear the blockage.

The "heater now then no heater then heater" is a sure sign of air trapped in the system - the bugaboo is "Is it trapped air or is it exhaust gas bubbles ?" The exhaust gas test tells you that.

Keith Carlson
10-19-10, 06:13 PM
I already disconnected the hose at the purge tank it coolant flowed freely.

What are exhaust gas bubbles and what are they caused from? What is the exhaust gas test? How is it preformed? Thanks!

Submariner409
10-19-10, 06:23 PM
I already disconnected the hose at the purge tank it coolant flowed freely.

What are exhaust gas bubbles and what are they caused from? What is the exhaust gas test? How is it preformed? Thanks!

Exhaust gas in the coolant is the prime indicator of failed head gasket(s) in a Northstar (or any other) engine.

The test consists of analyzing the airspace over the coolant in the reservoir for the presence of exhaust byproducts. Use this:

www.sjdiscounttools.com/lis75500.html

Keith Carlson
10-19-10, 06:27 PM
Thanks Sub, I was hopping it wasn’t going to be the head gaskets AGAIN, all ready been there and not going to go there again if that’s what the problem is.

Submariner409
10-19-10, 06:36 PM
Thanks Sub, I was hopping it wasn’t going to be the head gaskets AGAIN, all ready been there and not going to go there again if that’s what the problem is.

From your Post #1 - When the HG's were done, who and how ??? Are you sure that all 20 head bolt holes in the block were machined and either inserted/studded ?? ----If they weren't, you got gypped.

Keith Carlson
10-27-10, 07:19 PM
The head gaskets were done correctly by the dealership, I Paid through the nose for it.

I’ve been driving it to work and it’s like clock work I get close to work and the needle goes to 2:00 and 15 seconds later it’s back to normal. When I get close to home it does the same thing 2:00 and back to normal 15 seconds later.

Keith Carlson
11-06-10, 12:34 PM
Well it’s confirmed, I’m on my second round of head gaskets. I took the car to a friends shop and they checked the coolant for gasses and the test showed yellow meaning one or both the gaskets are leaking.
Is there a product out there that anyone has had any luck with? I’m not about to put another $6,000 into this car to have it fixed. Besides I believe I read somewhere it could only be done once?

RippyPartsDept
11-06-10, 01:52 PM
head gasket job shouldn't cost more than $3000 - we charge less than that... i think Jake charges even less than us

the hardest part is getting someone who has experience with this job and can do it right so that you don't end up in your exact situation

either your original head gasket job was botched, short-cutted, or worse - scammed - but more likely it was just a minor error due to inexperience or less than perfect attention to detail

depending on exactly how your original HG job was done you may have options

i would suggest you just get a salvage engine and swap it... cost way less too

Ranger
11-06-10, 02:08 PM
HG's can be done a second time by using "Bigserts" (oversized Timeserts). If it failed, it was probably not done correctly the first time.

Submariner409
11-06-10, 03:50 PM
HG's can be done a second time by using "Bigserts" (oversized Timeserts). If it failed, it was probably not done correctly the first time.

I would like to be the fly on the wall when this particular engine gets opened up again - I'll bet even $$$ that all 20 holes were not Timeserted.

RippyPartsDept
11-06-10, 04:11 PM
yeah, bigserts are what we use - even for first time HG jobs... i think that we switched to them when GM stopped offering the original timeserts via SPX (gm's special tool company) and we had to start directly ordering from Time Fastener

Ranger
11-06-10, 10:18 PM
I would like to be the fly on the wall when this particular engine gets opened up again - I'll bet even $$$ that all 20 holes were not Timeserted.

Very possible. It would be interesting to know.

RippyPartsDept
11-07-10, 12:48 AM
i would almost bet money that whoever did the job put some kind of heli-coil in there assuming that would do just fine

Keith Carlson
11-16-10, 12:50 PM
How does a little gas vapor in the coolant make the engine get hot and then cool down so quickly? Which is still happening like clock work after about 15 minutes driving or 12-14 miles on the express way. The additive I put in (Bar’s Leak One Step Head Gasket Fix) seemed to work? The whistle I had which the mechanic that checked for the gas vapor in the coolant thought was a leaking gasket is no longer present after adding the One Step.

Ranger
11-16-10, 03:33 PM
The vapor circulates to the ECT sensor as an air pocket. The sensor, no longer in contact with flowing coolant, picks up heat from the stagnant heating air and shows a temperature increase. Throttle up and the water pump spins faster and starts moving coolant which now sloshes through the system displacing the air and cools the ECT sending the temperature needle back to normal until the process starts all over again.

Keith Carlson
11-24-10, 04:27 PM
When a head gasket leaks do you always get white smoke coming out the exhaust?
I’m not seeing any white smoke I just have the fluctuating temperatures which is now happening 3-4 times within the fourteen mile trip to work.

Ranger
11-24-10, 11:48 PM
Not until it gets pretty bad. Won't see any at all in the early stages. Try wiping your finger around the inside of the exhaust tips. Is it dry or slimy wet?

Keith Carlson
12-08-10, 08:09 AM
Is this common? I now have a lot of steam coming from the engine bay area now when it gets hot. The last time the gaskets went this did not happen I just had white smoke out the exhaust. Being its cold (around 10-15) outside it’s hard to tell if there is any white smoke yet.

Submariner409
12-08-10, 10:30 AM
Steam from the engine compartment is a coolant leak, and Northstar head gasket failure is not known for leaking coolant out of the head/block joint in such manner as to cause an external leak.

Keith Carlson
12-08-10, 04:57 PM
What should I be looking for? When I got home last night I lifted the hood and steam was coming from the left rear area near the fire wall.

RippyPartsDept
12-08-10, 05:36 PM
driver's side or passenger's side?

if passenger side then i'd say it's probably the heater lines .. either silicone hoses gone or metal tubes rusted through

Ranger
12-08-10, 10:38 PM
Left is the drivers side. I'd guess one of the heater pipes that run along the rear head. They tend to rust out.

RippyPartsDept
12-08-10, 10:42 PM
left is driver's side (technically) but if you open the hood the 'relative' left is the passenger side... lots of people don't know the orientation thing (left always is driver's), so I try and always refer to passenger and driver rather than left and right

Ranger
12-08-10, 10:45 PM
Roger that. I knew what you where getting at.

RippyPartsDept
12-08-10, 11:33 PM
yeah, i figured as much. i mostly was saying that for the benefit of those who make the mistake ...

Keith Carlson
12-09-10, 03:49 PM
It is the passinger side and I also saw some coming from near the throttle body?

RippyPartsDept
12-09-10, 04:00 PM
you have the heated throttle body then i bet... there's definitely info on here in a bunch of other threads about fixing leaks there

Keith Carlson
01-29-11, 03:50 PM
What causes the upper radiator hose to not get hard? What’s the best way to find out if the coolant is flowing? The car is getting hot in a matter of minutes with it being 25 degrees outside and I still do not see any white smoke coming from the exhaust.
I forgot to mention the display told me the coolant level was low but when I removed the cap the reservoir was still at the proper level.

Submariner409
01-29-11, 05:26 PM
What causes the upper radiator hose to not get hard? Whatís the best way to find out if the coolant is flowing? The car is getting hot in a matter of minutes with it being 25 degrees outside and I still do not see any white smoke coming from the exhaust.
I forgot to mention the display told me the coolant level was low but when I removed the cap the reservoir was still at the proper level.

As the coolant warms, it expands by about 6 to 8 % of its cold volume. This is the reason that you need sufficient airspace in the reservoir - and this expansion raises system pressure to prevent water pump cavitation and raise the boiling point (at 16 psi) to 265 degrees.

Some white condensation vapor from the exhaust is perfectly normal during cold/cool weather. Burning gasoline creates a LOT of water vapor which cooks off the exhaust piping as steam, or drips out the muffler weep holes onto the driveway.

Coolant reservoir level sensor malfunction is common - it is primarily for Grannie notification, not for someone who checks engine fluids on a regular basis.

Keith Carlson
01-29-11, 06:05 PM
Why does the upper hose not get hard? I can squeeze it weather I first start it up and also when it starts to over heat with the needle is at 2:00 and the heater turns cold. Is this engine not circulating the coolant? Is it possible to take the thermostat out and see if it over heats? What would I do for a gasket if I did?

Submariner409
01-29-11, 06:10 PM
Circulating coolant or not, the very act of heating the coolant should pressurize the system to the 16 psi reservoir cap setting. If the hoses do not get fairly hard, you have system leaks or a bad pressure cap. Bad head gasket(s) will further pressurize the system and cause the coolant to blow out past the cap relief valve.

You could remove the thermostat and place it and a candy thermometer in a sauce pan of water. Heat the water, and the thermostat should begin to open at about 188 degrees and be fully open at 206.

Have you replaced the reservoir pressure cap, inspecting the tank filler neck for a bad cap sealing surface ?

BestTimesNow
02-16-11, 09:23 AM
Down near the water pump/thermostat cover there's a bolt-nipple with a 5/8" hose attached - that hose runs to a nipple at the top side of the coolant reservoir (NOT a coolant overflow hose which you may or may not have - that hangs down from the cap out the bottom of the car). The hose is called "purge line" and it automatically, 24/7, bleeds air and gases out of the system into the airspace over the coolant in the reservoir. Sometimes it or one of the nipples clog up.

With the engine cold, open the reservoir, disconnect the hose from the tank nipple and hold it in the open filler neck. Have an assistant normally start the engine - a few spits then a steady stream of coolant should flow. If not, then you need to find and clear the blockage.

The "heater now then no heater then heater" is a sure sign of air trapped in the system - the bugaboo is "Is it trapped air or is it exhaust gas bubbles ?" The exhaust gas test tells you that.

We had the exact problem with our 99 STS. Finally fixed it last night!!! The first indication of a problem was the weird temps due to flow and air in the line issues. We located a leak in the cracked overflow tank. We replaced the tank, but the problems still existed. Then we replaced the thermostat and water pump. The weird temps still existed and the heater would blow cold air at times.

We pulled the hose of the "Bolt Nipple" located near the radiator hose connection and it was dry. We poked a small wire into to "Bolt Nipple", it was plugged. We pushed through the plug and coolant then flowed out the "Bolt Nipple". We reattached the hose and it's OK now. What a simple solution to such a frustrating problem.

Many thanks for your help!!!!

Picture showing "Bolt Nipple" connection. (Screwdriver is touching it)

http://farm6.static.flickr.com/5178/5450898042_25a0c04f10.jpg