Overheating Issue (research threads included)

[Neomoon]

I have been dealing with a overheating issue off / on for about 4 months now. Since this issue has recently returned, I would like some direction on what would be the best way to handle this issue.

About three months ago I started noticing my temp would on occasion climb to the point where the "Check Gauges" light would come on. But the temp would not stay there for that long, by the time I found a safe spot to pull over the temp would return to normal. At this point I topped off my coolant fluids since I noticed they were a little low, I figured that was the only issue since the problem disappeared for a while after I topped it off.

The problem returned recently so I did some research here and decided to switch out the thermostat (kept it at the stock temp). Again the problem was fixed for a couple of weeks until it started getting worse and happening more frequently. The first thread is what I did to the car this weekend after having it overheat on me:

Thread 1

BUT! If it's already in your coolant system, you're supposed to use it or a dexcool compatible coolant. Don't just go buy any coolant you feel like unless you've completely flushed out the dexcool from your system. Sounds to me like you have a **** load of air in your system. Fill up the radiator with coolant and start the car with the cap off. This way, once all that coolant gets sucked into the block, you can add more. Once it's filled, put the cap back on. Make sure the cap is on right! The arrow saying RC-124 (or something like that) should be pointing towards the nose of the car. Once the cap is on right, fill up the coolant reservoir on the passenger's side of the engine bay. Once you're done with that, your car should be at the right temperature to start bleeding the system (if it isn't, just wait until it is). Open up the bleeder screw until you hear hissing/see steam. Leave it open until you get a steady flow of coolant coming out. If it's still steaming, there's still air in the system. Air doesn't transfer heat nearly as well as water or coolant does, so your car will over heat if it has air in the system! Like I said, once you have a STEADY flow (not little spurts) of coolant, you can close your bleeder valve. I'd then go back and check the coolant level, just to be safe (Warning!! Do not do this right after you run the car! Wait for the system to de-pressurize or else you will need medical attention for severe 3rd degrees burns! I'd wait at least 2hrs, just to be safe). Follow those instructions and you should have an air free coolant system in no-time.

I did this after buy a new radiator cap just to be sure, what troubled me was that I bleed the valve for close to 10 min (probably more) at which point it only squirted a steady stream of water a couple of times. Once it would start squirting water I would cut the valve off for a couple of seconds, and once I opened it again, steam would continue to come out. After switching out the cap and bleeding the system (the car had already been idling for about 30 min with the temp not going past the 3/4 mark) I drove the car non-stop for about 50 min including about 30min straight freeway. I figured my problem had gone away since I had no issues. That was until this morning when driving into work the temp gauge climbed pasted the 3/4 mark a couple of times and barely dipped into the "Check Gauges" limit twice (each only lasted about 30 seconds) before returning.

I'm leaning towards the following explanations given on the following threads:
Thread 3

If it gets hot all at once and then cools down Your low on coolant and leaking it somewhere.
These cars tend to get air pockets in the system and just get hot and the gauge just jumps up all at once and then goes back down. (My car did anyways)

Thread 4

Temperature fluctuations like you describe are in most cases caused by vapor locks forming and then clearing, and can be from a variety of sources like low coolant levels or head gasket failure.

Check for air in the cooling system. If you have the bleeder screw (3800 II) open it when the engine is hot and see if any steam or air comes out. If you find steam or air, then you found out how it's overheating. Then you would have to look at why the air is in there.

Your fans are working normally when they come on above half (indicated).

As for the when A/C is on, my A/C works and the fans come on right away when I select the system on.

Both of these threads tend to describe the temp fluctuations I am experiencing. Now my question would be what would be the best way to get this issue taken care of? I know there are a couple of things that could be causing this to occur (why air is getting into my system).

1. Could it be a faulty water pump?
2. Could it be a lower intake manifold gasket (from this thread)
3. Perhaps head gasket failure

Would a pressure test or a coolant flush be able to fix the problem? I'm kind of spinning my wheels here and need to get this problem fixed ASAP since this is my only means of transportation and my job is ~45min (with traffic) away from my apt complex. Please keep in mind I have no where to possibly perform any of these procedures so I will be relying on a mechanic shop for my repairs.



UPDATE:After all was said and done the mechanic confirmed my water pump had gone out, as well as a coolant flush. I should be by after work to pick up the car. This is a HUGE weight of my shoulders!! I hope this takes care of my overheating issues until I decide to switch cars.

[3800SoloWing]

Re: Overheating Issue (research threads included)

I hope to god your not running Dexcool. Check a couple of things to make sure you dont have a rotting engine. One, make sure the coolant doesn't have any trace of rust looking bits in it when you drain the coolant. Two, squeeze your upper hose when the car is cool, not running. If you feel it crunching on the inside, your in trouble. Leaks on top of that, if your coolant is dissappearing slow or fast, could accelerate the rotting because of the oxidation of the corrosion.

I had the same issue, and it lead me to a new engine all together. Dexcool ROTTED the block because it ate through most of the gaskets, and part of the hoses and got in the cylinders some how. Check those couple of things and give me a shout.

[Neomoon]

Re: Overheating Issue (research threads included)

Thanks for the reply, but why wouldn't I be running DexCool? This is the factory issued coolant. Sure there have been issues with the gaskets but it was not due to DexCool it was due to faulty gaskets used by GM.

Link1
Link2

I do recall squeezing the upper hose when I changed the thermostat a couple of weeks ago while purging air via the bleeder valve. However I don't recall feeling any crunching as you mentioned.

Are you recommending that I do a coolant flush first? I am trying to eliminate things one at a time so I don't end up paying for necessary repairs. Thanks again

[whitdog54]

Re: Overheating Issue (research threads included)

Yea ditch the dexcool. I opened my radiator cap and there was brown chunks everywhere...I had the system completely flushed and switched over. I couldnt believe how gunked up my coolant was.

[Everglades W68]

Re: Overheating Issue (research threads included)

My original water pump just went out at 167,000 miles. Not a bad repair. Engine temp is very stable/cooler now.

[3800SoloWing]

Re: Overheating Issue (research threads included)

Thanks for the reply, but why wouldn't I be running DexCool? This is the factory issued coolant. Sure there have been issues with the gaskets but it was not due to DexCool it was due to faulty gaskets used by GM.

Before I replaced the engine, I went through the following issues-

1 - engine clicking when you first start it and loss of power accelerating
2 - upper intake
3 - lower intake gasket
4 - upper intake (again) and lower intake
5 - water pump
6 - internally corroded radiator (tons upon tons of rust and goo)
7 - plugs and cylinder heads (rust and orange jelly looking sludge [dex-cool])
8 - new engine

All in all, about $6000 in work and parts BEFORE the engine replacement. If that doesn't say anything about how suck-ars dex-cool is, than I dont know what to say.

As of flushing the system, do it ASAPPP. If the bottom or your radiator doesn't drain like its supposed to, or you see black or brown chunks, that's an immediate sign of serious trouble. If you don't get it out soon, than you could face a new engine sooner than you think. When I yanked and replaced mine, my 'maro had about 104K miles. "Extended life coolant" I just run mean green, and never had an issue since. Its also cheaper, and more reliable!

[Neomoon]

Re: Overheating Issue (research threads included)

My original water pump just went out at 167,000 miles. Not a bad repair. Engine temp is very stable/cooler now.

Everglades, where you loosing coolant and having very wild temp fluctuations before you decided to switch your water pump? What was it that lead you to pinpoint the water pump was your problem. I'm just trying to decide how serious the issue is.

Before I replaced the engine, I went through the following issues-

1 - engine clicking when you first start it and loss of power accelerating
2 - upper intake
3 - lower intake gasket
4 - upper intake (again) and lower intake
5 - water pump
6 - internally corroded radiator (tons upon tons of rust and goo)
7 - plugs and cylinder heads (rust and orange jelly looking sludge [dex-cool])
8 - new engine

All in all, about $6000 in work and parts BEFORE the engine replacement. If that doesn't say anything about how suck-ars dex-cool is, than I dont know what to say.

As of flushing the system, do it ASAPPP. If the bottom or your radiator doesn't drain like its supposed to, or you see black or brown chunks, that's an immediate sign of serious trouble. If you don't get it out soon, than you could face a new engine sooner than you think. When I yanked and replaced mine, my 'maro had about 104K miles. "Extended life coolant" I just run mean green, and never had an issue since. Its also cheaper, and more reliable!

I'll get the system flushed out, however do you think this will fix my overheating issue? That's my ultimate goal, I don't want to continue driving my car knowing it could overheat causing further damage to the engine.

[FirebirdGT]

Re: Overheating Issue (research threads included)

I hope to god your not running Dexcool.

There is nothing wrong with Dex-cool, only people that don't know how to maintain it. Dex-cool has far superior cooling properties.

ONLY use the 50/50 pre-mix. IF you must use the straight coolant, NEVER use tap water, only distilled water. Using tap water is a major issue. Think of Dex-cool as high performance coolant.

I have 243,000 miles with Dex-cool.

[Neomoon]

Re: Overheating Issue (research threads included)

There is nothing wrong with Dex-cool, only people that don't know how to maintain it. Dex-cool has far superior cooling properties.

ONLY use the 50/50 pre-mix. IF you must use the straight coolant, NEVER use tap water, only distilled water. Using tap water is a major issue. Think of Dex-cool as high performance coolant.

I have 243,000 miles with Dex-cool.

Thanks for the info, unfortunately I have been adding tap water when I mix the coolant. The first time I did this was about 3 months ago, before that I never messed with the coolant since it was never a problem.

I've been running the past couple of days without problems, I'm assuming this is because the car is full of coolant since I'm constantly checking it. I do still think I'm losing coolant and plan on taking into a shop next week to have the issue checked out. I'm crossing my fingers it's something minor that a coolant flush or water pump will fix.

[96firebird311]

Re: Overheating Issue (research threads included)

I'm sorry I don't have time to read all that info up there.... but I figured I would share.

I too had troubles with overheating. Replaced the water pump and gasket, themo, ensured air was purged from system, etc. No real solution. When I was finally able to get my car to my father (a GM tech), he tore into it and discovered an intake manifold gasket leak. I believe he replaced upper and low gaskets while he had it. Ran absolutely flawless since then.

Just an avenue for you to explore.

[Neomoon]

Re: Overheating Issue (research threads included)

I'm sorry I don't have time to read all that info up there.... but I figured I would share.

I too had troubles with overheating. Replaced the water pump and gasket, themo, ensured air was purged from system, etc. No real solution. When I was finally able to get my car to my father (a GM tech), he tore into it and discovered an intake manifold gasket leak. I believe he replaced upper and low gaskets while he had it. Ran absolutely flawless since then.

Just an avenue for you to explore.

Thanks for the input, it does seem as if in the end I will have to replace the gaskets. Any estimation on how much this might run me? I'm already preparing some money for the repair. Got 1k so far, hopefully this doesn't get into the 2k+ level.

[flamingchicken]

Re: Overheating Issue (research threads included)

i too am kinda lazy about reading the all of the above, but i had trouble with overheating, and it all stemed from a bad water pump. I replaced the radiator, all of my hoses, and upper and lower intake gaskets to find that the source of my overheating was from my water pump. There was no fins on it at all, NONE! therefore it wasnt pumping water.
Along the way i did find that my lower hose was completely stopped up. Grab ahold of the lower hose and check it when the engine is cold, like after sitting overnight, and if its hard, then it may be clogged.
I also swapped out for a new radiator. all in all for a new radiator, upper and lower hoses, thermostat, and water pump i only spent maybe $350 (but i do work at a dealership) you should be able to get out a little more than that, if it isnt intake gaskets.
A good way to diagnose if it is a leak in the system is to pressure test it. It will not pinpoint the exact location (intake/head) but it will tell you that there is a leak. its better to diag a problem and figure it out before you go throw money at it.

[CaptDestruction]

Re: Overheating Issue (research threads included)

I have been experiencing the same issue for the past week. Just started looking into it and found this thread.
One question: Where is the bleeder valve to release the air that might be in the system?

Thanks for writing all of this up Neo and thanks for everyone elses input.

[flamingchicken]

Re: Overheating Issue (research threads included)

on top of the thermostat housing.

[Jaysan]

Re: Overheating Issue (research threads included)

if the car doesn't overheat but I can see and smell the coolant burning does that mean the heads are still good and only the head gaskets need to be replaced ?