Radiator issues

[AdVenture]

My Van is showing signs of over heating, the needle is moving from left to right. The Radiator has been replaced recently and the Mechanic at "Cap a Radiator" says he "Bled" the system of excess air. The signs I'm getting is on the highway she's fine. Off the hwy while at a light the needle goes to the right. The Mechanic at Meinekie says he "thinks" we have to replace the waterpump. The Parts guy at the Auto store told me it I don't need a pump he says it just needs to get Bled properly. He says it's cycling on the hwy and when it's not moving the air pocket causes the signs of over heating with the needle going to the right.

What do you think?

[Tech II]

Was the radiator replaced for this problem?

Yes, this engine has to be properly bled......the funnels with the adapters that attach to the radiator neck, work great.....

Is your cooling fan working? Was it possibly left disconnected when the radiator was replaced?

[achabacha322]

Most likely air in cooling system. You can bleed it yourself too.Let me know if you need instructions. Also check coolant level, is it low? What color coolant?

[AdVenture]

Old radiator had a small hole in it, the fan is working. Now this morning the car won't start so I missed a day at work.

[AdVenture]

Ok, The car didn't start due to a loose Starter wire. But here's where I'm at with the over heating issue.

Radiator - New

Radiator Cap - New

Fan - Operational

Coolant Fluid Clear Orange - Full no Leaks

System has been Burpped

What should I check next?

[Rolm]

Originally Posted by AdVenture

Ok, The car didn't start due to a loose Starter wire. But here's where I'm at with the over heating issue.

Radiator - New

Radiator Cap - New

Fan - Operational

Coolant Fluid Clear Orange - Full no Leaks

What should I check next?

If all of the above are good then you have a bad thermostat and in these cars it is a bitch to replace. If you are not handy I suggest you bite the wallet and let a pro do it. I think it's a 3 hour job.

[AdVenture]

Originally Posted by Rolm

If all of the above are good then you have a bad thermostat and in these cars it is a bitch to replace. If you are not handy I suggest you bite the wallet and let a pro do it. I think it's a 3 hour job.

I also noticed on you tube that I don't own a curved wrench to get to the underside of the part that covers the Tstat.
He wants to do the water pump at the same time...what do you think?

I edited my list because I forgot to add that the system has been burpped

This guy makes it seem easy provided you have the VW Bettle wrench.
http://www.youtube.com/watch?v=ZgLWR1dCXRM

[Rolm]

Originally Posted by AdVenture

I also noticed on you tube that I don't own a curved wrench to get to the underside of the part that covers the Tstat.
He wants to do the water pump at the same time...what do you think?

I edited my list because I forgot to add that the system has been burpped

This guy makes it seem easy provided you have the VW Bettle wrench.
http://www.youtube.com/watch?v=ZgLWR1dCXRM

I saw that video and it seems like a 30 minute fix. Those curved wrenches can be bought at any parts shop. I also thought of cutting a slot on top of the bolt when removed by doing this once you have the bolt started you can use a flat screw driver to turn the bolt all the way in and use the curved wrench for the final few turns. Seems no need to take it to a mechanic and get stiffed around $400

[Tech II]

First off, the engine has to be COLD to do it this way, b ecause your hands are around the crossover pipe.....

Second, I don't care if you have a special wrench like he has, if that bolt comes out hard, you will go nuts trying to repeatedly put the wrench on the bolt....it's like 6X's you put the wrench on to get one turn.....

What I do is, get a new throttle body gasket..... remove the throttle body......and then you have plenty of room to get at that bolt.....

[DeltaP]

If it been properly refilled and bled out and it overheats at stops or under 30-35 mph, but does not heat up at higher speeds, it indicates a lack of airflow through the radiator, i.e. a cooling fan problem.
If it heats up at highway speeds, but runs cooler at lower speeds,(lower rpm) it indicates a problem with coolant flow.

[AdVenture]

Situation Update: Tstat has been changed, water pump has been removed and tested (it's Fine), Heater core is fine, a reverse flush performed, and a pressure test. everything comes back as fine. The radiator "Specialist" says there's flow to the left side but it gets lost on the right side. He says he sees the Lower manafold gasket seal partially covering a hole and says that may or may not be the problem but wants $700 to replace and reseat the seal. There's no freaking way I'm paying him for a guessing game. I think its BS I paid for a Tsat I didn't need and a diagnostic that yeilded nothing. I'm out $400 and a car that still overheats. Since Mechanics are getting close to the same as dealer for labor, I'm taking it to a dealer. They didn't charge me for a part they replaced that didn't fix the issue. Different issue not the recent overheating.

BTW, now she shuts down randomly weather on the highway or while sitting still. i've stopped driving it till I get it to a dealer for a diagnostic.

[LMP]

It was not mentioned since the beginning but what you describe is typical of that 3.4 engine and has been seen across all forums covering all GM cars with this engine: blown head gasket is the common issue , and it brings all of the above: erratic temperature indication, trapped air (in fact stray exhaust) , erratic heater operation, boiling, loss of coolant...
Make sure you do not run in circles around that problem without addressing it....

[j cAT]

pressure test the coolant system. also see if the coolant has exhaust pressure pulsations in the coolant system.

with exhaust gases entering the coolant system the coolant flow will get disabled. the water pump pumps water not air , the coolant continues to have air in it .

thermostats should be replaced 4-6yrs or 60-80,ooomi.

water pumps usually will not corrode on the impeller if the coolant is replaced and distilled water is used at the 50% or more of dexcool.

pressure testing should show if you have a leak or the exhaust is blowing into the coolant.

with the coolant pressure cap off engine cold , start engine run until hot see if the coolant bubbles as the engine exhaust pulsates.

I would be surprised if it is a dead gasket with all those experts saying that they are confused as to the cause.

[AdVenture]

LMP and J Cat, I stated that a pressure test WAS done and came back fine. I drove my car home from "Cap a Radiator" till I can get it to a dealer. I took the Turnpike home with no issues other than the needle going from far left to 3/4 to the right. The car's performance ran as if it had no issues at all. Total miles home was 19 miles in stop and go traffic (lights). Since I'm between jobs this will have to wait a few weeks.

BTW, anyone know what a dealer is getting for diagnosics these days? Last I had one done in 2008 was $125.

[AdVenture]

The Verdict is in! Chevy dealer found the problem as I knew they would. Apparently, the van has a bad head gasket which is allowing the antifreeze to enter Cylinder #2. this is what's causing the excelleration and over heating issues. Dealer price to fix it is $2,480, Mechanic $1,200-$1,300.

BTW, that's providing there are no cylinder issues...i.e. warped/bent heads.