Troubleshoot overheating prob

The water pump is turning, right? (Just checking...) ;)

Not sure if you can still do this on an LT1, but the stethescope/screwdriver to the ear trick can help diagnose a bad water pump.

Do you have an oven thermometer? Maybe the sender or gauge has gone bad. Let the car cool off and take the rad cap off - start the car with the cap off and the thermometer in there... Or an infrared thermometer to measure actual block temp - maybe it's not really overheating. When the oil pressure gauge went in the wife's Beretta (digital dash) it would randomly sweep from 0 to full and back again.

I believe the LT1's have a coolant fill procedure that's required to bleed any air out.

Is it possible the radiator is full of crap? I've heard of stuff like plastic bags getting stuck in the gap between the condenser and the radiator.

Lastly, the front air dam is not optional on any Camaro/Firebird built after 1982 - remove it and your car WILL overheat while driving down the highway.

Ray

On Sep 14, 2:23 pm, ray wrote: [snip]

It's one of those water pumps that is driven by the camshaft and not off of a pulley and the serpentine belt :( I think the only way I can check it is to remove the thermostat (replace the housing) and start it up, and then check to see if water is pumping (looking down the radiator fill neck)

You know, there is a noise (sounds like a bearing going out) that has been on-going for 2-3000 miles - I was thinking that maybe it was the alternator bearing heading south of maybe even the A/C compressor. It's difficult to tell with the 18" 3.8" drive extension. It could be the alternator, water pump, or the idler pulley (it sounds the same from all three) :) :( Maybe I should get a real mechanic's stethoscope.

I'll get one and give it a try.

Yes, I filled the radiator, started it up and brought it to running temp, then bled the system using the two bleeder screws near the thermostat housing.

I checked for plastic or bags, etc in front of the radiator, but didnt check in-between the radiator and condenser - I'll do that too.

Thanks!

I bought a mechanic's stethoscope (a heck of a lot more sensitive than a screwdriver/etc) and i've determined the high-pitched squealing sound is indeed coming from inside the water pump housing. I've called Oreilly auto parts - they show i purchased the new water pump last July, so I will take it off and they will give me another new one.

It's been over a year or 20 thousand miles, give or take 1 or 2 thousand. Shouldn't this $150 water pump last longer than that?

Yes, it should last longer than that. However the national chains that carry "lifetime warranty" parts use Chinese made bearings, seals and anything else that they can cheapen.

Consider buying from a different source or you will replace it again in another year.

That car requires a special t'stat that actually has 2 opening/closing valves. It's part of your TPI and reverse cooling system. Don't ruin your engine! s

On this car, the fans that merely cool the engine, w/ac off, are not turned on by the sensors until the temp reaches approximately 225 or more degrees, maybe 228(?). Seems high, but so be it. The engine is designed to run at these high temps; GM makes a 160-degree t'stat for it but very few GM dealerships carry them and most parts guys don't even know they exist. (They may be listed only in the hi-perf. GM catalog--and with a valid GM part number). I'd try to stay with the oem temp t'stat anyway; most likely a 195-degree is the only temp listed in the standard parts manual. Your diagnosing probably will turn out to be a water pump, based on additional info you provided below; spend a little more & get a good pump, like from GM. Ensure again you don't use an improper t'stat, as IIRC AutoAone, Advance, and prolly others carry only standard, non dual-opening valves (one upper and one lower) which can DESTROY your engine. Your proper t'stat will cost about twice what those std ones cost. Compare the 2 side-by-side at a GM dealership, & you'll see the impt. difference. GM is the only place I'd trust to find the correct one. HTH, s

I appreciate your mentioning this,SD... This feature is special to the Gen II LT1 engine.

Something else must be going on as well, since he said he had had no previous problems until this overheat started. It was then that he replace the thermostat with the STANT one.

The water pump may be the substantive issue, but the use of the proper stat is critical for that reverse cooling flow engine.

Great sugestion, Kruse!

Last night, I had some time to sit down and examine the "new" water pump that I was about to install today. What a horrible piece of workmanship (I shouldn't use the word "workmanship"). I took pictures of this "new" pump ... the thermostat mating surface had a metal "nipple" (or large bur) significant enough that I would have had to use a file to remove. Plus I would have had to use the file to smooth

The glue used to adhere the stainless pipes (that the various water hoses clamp to) to the water pump - that glue had trails running all around the pump. The casting surface of the whole of the pump, in general, was rather rough ... you could compare it to 80 grit sandpaper.

So I called the parts house this morning and asked them to order in an AC Delco water pump and that I wanted to trade in this junky "new" pump I had. So they had the AC Delco pump within an hour. What a heck of a DIFFERENCE. We put the Delco unit next to the "3rd party" pump and the difference is like night and day. All machined surfaces were smooth and nick and bur free... even non-mating surfaces were machined on the Delco. The overall casting surface of the pump was smooth, almost like 220 grit sandpaper.

Difference in price? $12 more for the Delco. It's well worth it, even it were $30 or 40 more. This "MASTER PARTS DIVISION" water pump should be priced at $60, not $147.00!!

You're right! I bought a Stant SuperStat, which has a nice heavy-duty build to it. Even the valve mating surface is rubber sealed. And yes, it has the 2 stage valves. This unit was around $17 versus $3.50 for the "standard" unit.

On Sep 14, 8:43 pm, "sdlomi2" wrote: [snip]

Thanks for the suggestions. The Stant SuperStat thermostat unit I bought, which is a heavy-duty construction, 2 valve unit, has a rating of 180 degrees (the rating specified by GM). This SuperStat set me back $17 USD.