: SLS overheating help? please?



juicedfbody
02-16-09, 08:49 PM
Hello im new to this forum, my 1999 seville is overheating, once it gets to normal temperature steam starts coming out of the coolant recovey tank after a while coolant starts to come out and after a while it starts to overheat, i replaced the water pump and thermostat checked the purge line does not seem to be clogged, i tried conecting the cooling fans direct to have them on all the time and just noticed today that they run in the opposite direction, driver side fan turns counter clock wise and passenger side fan turns clock wise, is that my problem???? IF it is how can i fix that? Bad relay???

Destroyer
02-16-09, 09:26 PM
The fans are not likely to be the problem. Get the coolant checked for exhaust gasses. Don't want to get you all "riled up" but the symptoms of a bad head gasket are there. I went through the same thing and had the t stat and water pump replaced as have many others. You came to the right place as there are many knowledgeable folks in here that will be more than happy to be of assistance. The end result is usually the same. Good luck and keep us posted.

juicedfbody
02-16-09, 09:45 PM
I did notice today that once it got to normal temp. and steam started to come out the cap when the fan kicked in it stoped steaming, and only one fan was working

Mark C
02-17-09, 07:14 AM
How hot is it when you first notice steam or water coming out of the overflow? If its below 250 it could be just a bad radiator cap. How many miles on the car? Does it overheat at idle or do you have to be driving it, does it do it around town, on the highway or both. Need a little better description of the problem, but it doesn't sound good.

Submariner409
02-17-09, 09:59 AM
Both fans should turn in the same direction as they are "pullers" attached to the rear of the radiator and pull air through rather than push (blow) it in from the front. If one fan rotates backwards its because the wires have been reversed.....a DC fan will run in whatever direction you want simply be reversing polarity of the + and - wiring. There are 2 30 Amp fuses and 3 (?) relays in the underhood box - the relays determine when fans are on and whether they are wired in series (slow) or parallel (fast). You need to do some troublshooting because airflow, not mechanical engine parts, seems to be your problem.

The fans should go to slow at about 223 degrees (or when any a/c function is commanded) and to fast at 235. The pressure cap is either 16# or 18# depending on engine year. This gives a boiling point of about 265.

tateos
02-17-09, 11:23 AM
HG - Destroyer is correct - you can do all the tests, but it is a classic headbolt/headgasket failure

juicedfbody
02-17-09, 11:34 AM
Im not sure about temperature in numbers but starts steaming after a while of being at normal temperature and then a little while after its been steaming coolants starts to come out, all this happens before the needle gets one line past the normal temperature. I did buy a new cap but its still the same, overheats idleing and around town ive only driven it on highway once and did not overheat, it does overheat faster when i drive it than its just idleling, it has 132000 miles.

Submariner, when i first got the car it came with a 18psi cap, when i bought one from parts store they gave me a 15psi cap, it is a 1999 Seville SLS

tateos
02-17-09, 11:37 AM
The reason the coolant comes out is the head gasket is leaking and the exhaust gases are being forced into the cooling system, and that is forcing out the coolant

It's the head gasket. The real question is: how much do you like the car?

juicedfbody
02-17-09, 11:47 AM
Awww you just killed me right there, i love it but have no money.

CaptainFishpond
02-17-09, 11:54 AM
How much coolant is in the system? Are you sure its full? No visible leaks?

Ranger
02-17-09, 11:59 AM
Unfortunately, it does sound like a head gasket. Get a test kit and test the coolant for exhaust gases or have it done to confirm it before throwing any more parts or money at it.

juicedfbody
02-17-09, 12:21 PM
Yes its full and purge tank is to where its supposed to be thats another thing, system is full to my eyes and the computers says, check coolant level, i have disconected the top radiator hose filled with coolant and put it back, filled the recovery tank with coolant to the mark and it still says check coolant level, i did squeeze the top hose with the cap on and i heard air coming out of the cap, is that supposed to happen, no visible leaks.

juicedfbody
02-17-09, 12:25 PM
Ranger, when i checked the purge line coolant came out but is was not a steady stream, is it supposed to be a steady stream?

tateos
02-17-09, 12:34 PM
Ranger, when i checked the purge line coolant came out but is was not a steady stream, is it supposed to be a steady stream?

Not if there is air in the system - that is what the purge line is supposed to purge - of course combustion gases are also "air"

CaptainFishpond
02-17-09, 12:49 PM
Did you do the water pump yourself or did a shop do it? I did a water pump on a 4.9 and left a big old air bubble in the system and the car overheated.

juicedfbody
02-17-09, 02:14 PM
I did it my self but how would mechanics supposed to replace a water pump without leaving air in it?

Submariner409
02-17-09, 03:02 PM
When the system is gas/air free then the purge line will emit a steady stream of coolant. The purge line is actually a pressure side (discharge) pump bleed which keeps the coolant from aerating and causing pump cavitation.

Dealers and radiator shops use a vacuum machine which literally pulls fresh coolant through the entire system, eliminating service time and "comebacks" due to air locks.

DIY jobs require some clever burping, filling, running, and refilling tricks before the system is once again air-free.

BUT, if a head gasket is leaking gas into the coolant or if you have a leak somewhere, trouble and frustration.

tateos
02-17-09, 04:04 PM
This sounds like it is describing the recent SBC, but is this not close to describing the Northstar? If so, I think it explains the purge line:

Some GM vehicles may be equipped with a reverse-flow cooling system which operates differently than a conventional type cooling system. The specialized components of this system include a gear-driven water pump with cast internal cross-over passages, an inlet-side thermostat and a pressurized high fill coolant reservoir. In this system, coolant is routed from the water pump, directly to the cylinder heads. When the heads are adequately cooled, any accumulated vapors are vented off, and the coolant then circulates through the engine block. After the coolant leaves the engine block, it returns to the water pump, moving through an internal passage into the radiator. There is a thermostat on the inlet side of the pump which meters the coolant temperature as it flows from the radiator and tries to enter the water pump casting. The water pump, which is driven by the camshaft, which is the center of the system, has cast internal passages which route coolant through the engine without sending it through the intake manifold, eliminating possible leaks. The gear-driven pump ensures coolant flow even if the drive belt breaks. The reverse-flow cooling system is advantageous because it reduces the overall cooling system pressure and basically eliminates pitting or disintegration of the water pump and seal. In addition, routing the coolant to the cylinder heads first promotes higher bore temperatures and less ring bore friction, increasing output and horsepower. Due to the increased temperature of the cylinder walls, which created higher oil temperatures, engines with reverse-flow cooling systems may be equipped with an engine oil cooler or use synthetic oil.

Ranger
02-17-09, 05:22 PM
Tateos, with the exception of the gear driven pump, it does sound like the Northstar.

Juiced, I don't think the purge line will have a constant flow at idle. I believe it will sort of spit and flow will increase with RPM.

Mark C
02-17-09, 07:24 PM
i did squeeze the top hose with the cap on and i heard air coming out of the cap, is that supposed to happen, no visible leaks.

No, that should not happen, there has to be something wrong with your cap, or the top of the surge tank itself.

juicedfbody
02-18-09, 12:28 AM
Thank you guys for all your help, i will replace the recovery tank and another new cap another question ive been thinking alot about is, i cant buy a new recovery tank at the moment, and have not found a used one for this particular anywhere, i know it wont sit correctly where its supposed to but if i connect a pressurised recovery tank from another car will it work the same as if it was the original one???? Lets say from another northstar engine Eldorado maybe???

Ranger
02-18-09, 12:10 PM
If it is from a Northstar it will have all the correct hose nipples and should work, but different years had them on different sides which might cause some mounting problems.

CaptainFishpond
02-18-09, 12:12 PM
I should have one, Ill post later once I get to work.

CaptainFishpond
02-18-09, 04:14 PM
Sorry the only one I have is off an 00 DeVille, and its cracked anyway. I show quite a few on Car-Part though.

juicedfbody
02-18-09, 04:41 PM
Thanks, Car-part? Website? Ok more info on the car, i got both fans to work the way they are supposed to (pull air) i was driving around town and temoperature went half way between the middle mark and the hot mark, drove it home(two blocks) parked it and left it running, the temperature stayed on the same place, opened the hood and noticed that on the plastic parts of the radiator on the passenger side it was hot top to bottom and on the driver and the driver side of the radiator was hot, normal?? Also reved the engine a few times and the temperature started going down reved it a few more times and it went back to normal. After a while turned it off let it get cold enough to take off the cap started the car again and notice the coolant was going down and then back up, reved the engine coolant went down and back up after a few more times every time i reved the engine coolant came back up a little higher, stoped reving the engine and after a few more minutes the coolant level started to rise untill it overflowed and spiled a lot of water, could the coolant system be blocked somewhere?

tateos
02-18-09, 07:19 PM
Put the cap back on

Ranger
02-18-09, 09:30 PM
When you rev it, it WILL go down a little because the flow is increasing and it is drawing coolant from the tank. When you decrease the RPM's the opposite happens,. Hence the name, "surge tank". It finally overflowed because boiled. With the cap off it is at atmospheric pressure and a 50/50 coolan water mix will boil somewhere around 220 I think. With the cap on it is under pressure and the boiling point is raised to 265. You have only a few minutes to run it without the cap before it boils over.

juicedfbody
02-18-09, 10:27 PM
Ok i will see if i can find another surge tank to replace the old one and a radiator too maybe?? I will keep you posted when i do to let you guys know what happens, thanks for all your help.

CaptainFishpond
02-19-09, 08:13 AM
do a search on www.car-part.com

tateos
02-19-09, 12:32 PM
Ok i will see if i can find another surge tank to replace the old one and a radiator too maybe?? I will keep you posted when i do to let you guys know what happens, thanks for all your help.

Even after changing all the parts, I think you will still have the same problem and find it is the HG. I hope for your sake I am wrong.

Destroyer
02-19-09, 08:50 PM
Even after changing all the parts, I think you will still have the same problem and find it is the HG. I hope for your sake I am wrong.
I think we all go through this stage when it happens. :cookoo:

benmack
03-16-09, 04:07 PM
Did this problem end up getting resolved? I have a 99 and the same problem. I have replaced the fan sensor and had tested for bad HG (mixed liquid with coolant) and passed. When I take off from stop signs I can hear water bubbles. If you found something out I would appreciate the advice. Thanks!

Submariner409
03-16-09, 04:25 PM
Read Jim D's post in your similar thread in here. If that purge line is clogged, due to the nature of the Northstar cooling system, you'll never get it bled of air.

Where do you hear bubbling - down in the front console area or up front toward the coolant surge tank ?? Are you losing coolant during every drive ?? Is the coolant filled to halfway up the surge tank, COLD ?? (If coolant is overfilled it will expand and overflow.....that's what the air space is for: expansion.)

benmack
03-16-09, 04:34 PM
Sorry, I didn't read the reply to my post until after I made this post. I hear it in the console (sounds like coming out of the vents). I appreciate the help from all of you.

Ranger
03-16-09, 04:38 PM
What you are hearing is in the heater core. Follow Jim's advice for starters and continue any further questions in your original post.