Thermagasket

[Kev]

Originally Posted by rfishing

I had to return the Laser Thermometer for another one. This basically summarizes it.

- Upper hose is about 10 degrees hotter than lower hose.

- on Inward side of radiator, basically left and right area is hottest 180-190s, and inside readings are 30-40 degrees less varying 120-150s.

- On entire front side of radiator the readings are colder, on front left and right 80s, and insides 50-70s with temps decreasing toward the bottom.

Can anyone tell me if those are normal or abnormal readings?

Take the thermometer and check a few other cars (that do not have coolant issues) to see how they read. Basically most of them should be similar. That should give you an idea as to how yours is.

[rfishing]

I spoke with a mechanic, and he told me the readings on the front of the radiator should be hot, the same as on the back side. He says, my readings are all cold on the front of the radiator indicating the entire front is clogged up.

Basically, I am operating with half a radiator.

[C170B]

LOOK AGAIN.

I may be wrong but I suspect that you are reading temps on front of A/C CONDENSOR , it sets in front of radiator 100% blocks a visual on radiator making it difficult get the laser beam on front much less do scan.

That A/C condensor is blocking more than a hot dog wrapper on front end of a NASCAR racer.

There is no reserve cooling capacity on any production automobile unless it is a POLICE SPECIAL w export suspension package. That meams any problem can and does send the car us over the edge.

There seems to be a owner bonding w the N* mystique and we don't want to let go - We need to get a more complete solution for overheating instead of piecemeal repairs.

[rfishing]

You are right, I checked again, and there is a very large separate unit in front of the radiator. It is same size as the radiator. That is what I was scanning and getting the cold readings off of.

There is another smaller unit to the passenger side in front of radiator, for some reason I thought that was the one for AC unit.

So basically the readings off of the back side of the radiator are the only ones obtainable.

Argggghhhhh........

I got this from troubleshooters.com

Normal radiator, not sure if this applies to Norstars maybe someone can confirm it.



Basically should be hot on inlet side, and get colder toward the outlet side. I think mine is hot on both sides, and 20-30 degrees less in middle areas. Interesting thing is, mine the upper hose is hotter by about 10 degrees than lower hose.

[WillGlueIt]

This thread reads like War and Peace, long and at times frustrating. I wish a pressure test had been done on each cylinder, no bubbling in the surge tank would be enough for me to rule out an existing head gasket issue.

I did catch one thing that rxauto stated, "5-7 heating and cooling cycles" is the active life of the product (Thermagasket). I think this product was left in the cooling system far to long in rfishing's case. To many cycles, I bet the hardened product has clogged the radiator to some extent. Par for the course with most "stop leak" products. Even if the radiator is only a year old.

If this was my car, I would roll the dice and replace the radiator. A clogged radiator should be easy to detect by a mechanic of even marginal skills. A radiator is a radiator, even a radiator that is cooling a Northstar. I would not go for the "rodding out", sounds like the mechanic wants a quick payday. I bet removal of the radiator is not required to perform the "rodding out" proceedure.

I would also flush the cooling system again, and add the coolant supplement (equivalent to six tablets) along with the proper mix of Dexcool and distilled water. I would hate to see the heater core clog up next.

[rfishing]

Question, why would you opt to replace radiator that is one year old instead of rodding out?

In theory:

1. I flushed out radiator with garden hose placed inside the upper radiator hose, and water was flowing smoothly out of the bottom radiator hose, doesnt that mean I have good flow?

2. Since I have good flow, how can the radiator be clogged?

3. Temp readings at idle, upper hose was 10 degrees hotter than lower hose, doesnt that mean radiator is working properly?

Unless I see it for myself, I am skeptical about the radiator being clogged.

This mechanic is supposed to be the expert whom rebuilds and rechecks every engine after it is rebuilt for proper operation. He was quick in finding the radiator as a problem, and tried to show me with hands how it is clogged. I bought the laser thermometer, and those results are already posted previously.

[WillGlueIt]

1 & 2. From what I remember about radiators, the path is not one snake like peice of small diameter tubing all coiled up running from one end of the radiator to the other. There are multiple paths (2, 3 or more). You can still have flow, just not enough flow. I bet one or more of these paths are blocked or restricted by chunks of hardened Thermagasket material. This would reduce the cooling capacity of the radiator.

3. At idle is not the same as under a load, driving up a mountain or doing 85 mph on the freeway on a warm day is not the same condition as at idle (no load) when it is 70 outside. Your heater core alone might be enough to cut the mustard at idle.

Drive that car up a mountain with the heat off and check out that radiator at the top. I bet it is steamin' hot on the inlet side. It's like having a small Honda Civic radiator, installed in your Caddy.

Spend the $359 on a new radiator, running a "Roto Rooter" snake type device through the existing radiator shouldn't cost that much. A new radiator installed should be close in cost to $359, if you call around town and do some shopping.

[denscor]

Hey just thinking about your problem,has anyone changed the radiator cap? sometimes you get a bad one!

[rfishing]

Got the car back yesteday after radiator was rodded out, found to be 25 % clogged. They put in new thermostat and topped off cooling system, and changed my oil / filter.

Decided to go down mountain for test drive, but now local driving 207 average temp. Got on highway to mountain pass went about 3 miles, got off cause temp seemed high at 205-210 steep on ramp and slight incline on highway I should add. After exiting highway, drove for 4 more miles mixed lights and straights at 30-45 mph. The temp during this time was going higher 210-218, as I start moving the temp goes down slightly. I thought worst case is happening again, so I got out when the temp was 219, Popped the hood and coolant was dripping out the overflow tube. Temp only 219 and trickling out, not flowing. I drove a few more miles after it cooled down to 200, and temp again went up to 218. I called the mechanic and he basically told me, "well you knew you had a blown head gasket before using thermagasket, so nothing else we can do." "You have good radiator and thermostat", if you call around and find a new engine I will put it in for you. He wont do a head gasket on that 4.6 engine, and claims it is basically a throw away engine. This baffles me because before doing radiator he said, negative for blown gasket due to block test.

On way home, with 20 minutes of stop light traffic, even the slightest incline the temp goes up to 207-214, on slight declines it goes down to 198-204. After arriving home and parked, I tried running heater on high in econo mode with 2000 rpms and the temp went down a few degrees, then began slowly rising. I put climate control to automatic and heat on high, then temp went down from 218 to 208 at 2000 rpms before stopping engine. I am trying to tell if the water pump is pumping at high rpms, does that sound right?

This morning I checked coolant level expecting it to be at least a 1 gallon low, but to my surprise it is only 1 pint to top off, if you can call that low?

Have I gotten anywhere? Can anyone see something from my details that I am missing? Basically radiator is clear now, radiator cap good, new tstat, fans both working and tested by mechanics.

[zonie77]

Please check the radiator temps with the infrared thermometer again.

[94greencaddysls]

If you fill the surge tank to the top and install the cap then you will have some overflow out of the tube due to it being overfull and expanding. You also must take into account that the northstar radiator is not the average radiator. There is an oil cooler on the battery side of the radiator and transmission cooler on the other side. The cooler in front of the a/c condenser is a power steering cooler. Make sure you are getting flow through your evaporator onto your radiator. Also what are the outside temps where you are? My car regularly runs into the 225 range with all new hoses, water pump and new assembly, and a new radiator. My car's had a headgasket go out at 115,000 and was replaced and have had no trouble since but it ran the same temperatures now that it did before it blew out. If you drained the system entirely then there could be air trapped in the system and it may take awhile to get it worked out. Make sure the water pump air bleed pipe is free of debri with compressed air.

[donwon]

Last week I put some radiator flush in my 89 Seville and ran it for 3 hours at idle and 20 min. at 2000 rpm with heater on high.
The temp stayed around 200 degres.
I then tried to drive it and temp went to about 240 within 2 miles.
Last night I put in some more heavy duity flush and a new Tstat
let it idle for about an hour. Temp stayed from 188 to 196.
I then drove the car and the temp has gone to 206 one time.
I have left the cleaner in the car and will drive it a little tomorrow morning and it the temp stays within this range I will replace the coolant.
My problem started when I put the pellets in the radiator.
I even tried the K&w Block seal.
I guess something in the engine was stopped up and the flush got it uncloged.
No more running out the overflow for now.
I have some of the coolant tabs but I am afraid to put them in.
Is there anything else I can use.
Before I added the tabs I had some kind of silicone that is suppose to coat the inside of the block and it ran fine,but the heater only blew cool air.
Now I got heat.

[Kev]

Originally Posted by donwon

Last week I put some radiator flush in my 89 Seville and ran it for 3 hours at idle and 20 min. at 2000 rpm with heater on high.
The temp stayed around 200 degres.
I then tried to drive it and temp went to about 240 within 2 miles.
Last night I put in some more heavy duity flush and a new Tstat
let it idle for about an hour. Temp stayed from 188 to 196.
I then drove the car and the temp has gone to 206 one time.
I have left the cleaner in the car and will drive it a little tomorrow morning and it the temp stays within this range I will replace the coolant.
My problem started when I put the pellets in the radiator.
I even tried the K&w Block seal.
I guess something in the engine was stopped up and the flush got it uncloged.
No more running out the overflow for now.
I have some of the coolant tabs but I am afraid to put them in.
Is there anything else I can use.
Before I added the tabs I had some kind of silicone that is suppose to coat the inside of the block and it ran fine,but the heater only blew cool air.
Now I got heat.

Your heater core was clogged and it seams that the flush agent has opened it up enough to restore heat. once you have flushed the cleaner out and have refilled the proper coolant mix (50/50) you need to use the GM pellets as they help to seal the aluminum block from leaking. With the system cleaned out the pellets should not stop flow but merely seal up porous areas and prevent future leaks at gaskets between dissimilar metals (aluminum block, cast iron heads).

According to the experts you will be very unhappy in the near future if you choose not to use the pellets or their equivalent.

It's your call.

[denscor]

Another thought,would putting a cooler thermostat help? Maybe 180 or 160?

[Ranger]

Originally Posted by denscor

Another thought,would putting a cooler thermostat help? Maybe 180 or 160?

Don't reengineer the system. The only way a thermostat is going to help an overheat problem is if the thermostat itself is causing it. Otherwise it is just a band aid and will cause other problems. Use what was designed and tested at the factory.