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chev van with 5.7 runs cold

My friend has a 93 Chev conversion van with 5.7... poor heater output. He has an aftermarket temp guage that shows engine runs about 125 degrees F. He also told me the Dealership replaced the thermostat and it didn't seem to help. I attached my Snap on MT2500 and confirmed that ECM sees about the same temperature as his guage does. We headed down the road (it was about 35 to

40 degrees F that day) and I watched engine temp fall to about 110 F. Then he shows me this receipt from the dealership which I will quote below:

CUSTOMER STATES HE NEEDS A NEW THERMASTAT (yeah, that's how they spelled that) VAN HAS POOR HEAT LAST FEW DAYS. DOES NOT SEE ANY LEAKS ON GROUND AND HAS NOT ADDED ANY COOLANT NOTE: HAS AFTERMARKET TEMP GUAGE, BOTTOM LEFT OF DASH IS ACCURATE VERIFY CONCERN, CHECK FOR LEAKS NONE, ENGINE RUNNING COLD, SUSPECT THERMOSTAT REPLACE THERMOSTAT AND RADIATOR CAP. CAP LOOKS OLD, TOP OFF COOLANT AND BLEED SYSTEM. ROAD TEST. ENGINE STARTED TO COOL OFF ON ROAD TEST, CONSULT WITH 512. RECHECK FOR AIR IN SYSTEM, NONE. SUSPECT THAT THE INTAKE MANIFOLD GASKETS TABS HAVE ROTTED THRU AND LEAKING COOLANT BACK INTO ENGINE. WILL HAVE TO REMOVE INTAKE MANIFOLD CUSTOMER DECLINES, SEE ESTIMATE.

Anyone ever heard of such a thing causing low temp?? ... leaking gasket that isn't dumping coolant outside of engine, nor into crankcase as there is no coolant in oil or white smoke in exhaust?? Can this be just allowing coolant flow that is bypassing the thermostat and keeping engine temp very low??

I'm assuming the dealership really did change the thermostat... "assume" is a dangerous word... but they billed him 288.03 total! Ha! Estimate was $85 (I guess to just see if heat is really poor), then revised to $250.00, then revised again to $299.00 !!!! Below that is another estimate: INTAKE MANIFOLD GASKETS: $495.00 PLUS LUBE OIL AND FILTER: $29.95

at $300 to do the thermostat, I'd guess the intake gasket job would get "revised" a couple times along the way as well??? And experience or thoughts regarding this engine running too cold that can be something other than thermostat bad??? Thanks!

Reply to
In2hoppn
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Sounds like mebbe they didn't put a new thermostat in....I would pull it out and check it in a pot of water on the stove to know for sure. Just got thru checking mine and I know it works....not hard. Good Luck....Pete

Reply to
Pete

I had a 140 degree thermostat in my Blazer for a while. Makes me wonder if they put in a 115 degree summer stat, instead of the 180 or 195 that they ought have put in?

In any case, shops that constantly jack the price up during the job, I don't have a lot of respect for them.

I know of no other reason for running cold, other than stuck open or low range thermostat.

Reply to
Stormin Mormon

My thinking exactly! Are these places THAT desperate to make money? To charge that much and still not fix it?

Reply to
In2hoppn

I didn't think they made a thermostat that cold! I would certainly never install one if they do. Proper engine temp is important for more than just good heater output.

I googled the part number from the slip... chevrolet thermostat 10190925... and got lots of results showing that as a 195 stat. Of course, it don't mean they actually changed it. And there is always the possibility of installing a brand new defective one. I tried to see if it looked like it had even been apart, but it's not easy to see and it is a bit of a pain in the butt job to get at being a van... I certainly don't want to do an intake gasket on it. Vans are the worse thing to work on in any make vehicle... they should make the dashboard, hood, and windshield all one unit that swings open... then they would be nice to work on... maybe I should patent that idea in case they ever decide to design vehicles to be worked on : ). But why would they do that? Especially if most of the work the dealers are doing are never a problem because they aren't really doing it? : )

I also agree and have never known of any other reason for running cold except of course low coolant or bad pump making sensors and heater core stay cold... and for not long of course before overheating! This van runs and drives fine, just poor heat and low engine temp confirmed by different sensors. I think he just got himself "boned" by the dealership!

Thanks for your imput!

Reply to
In2hoppn

I had this problem on a 94 PU, 350. In everything but the coldest weather, it would get up to temp, but it would take 15 minutes on the highway to do so. I had asked several mechanics about it, and no one had any suggestions. I even changed the thermostat twice myself with no results.

Ten years down the road, I was having an new engine installed, and the mechanic called saying he couldn't find a thermostat to fit it. The manifold was a very poor fit for a standard sized thermostat, and he couldn't find one that would fit to suit him.

After a lot of phone calls we finally found out that some of those thermostats require a rubber O-ring with a groove in it, that fits around the thermostat before it is installed in the manifold. When you check yours, I would suggest doing it yourself, see if the thermostat is a real poor fit in the manifold. If so, this O-ring could be your problem too.

My truck now heats up very quickly. After adding a new heater core a few months later, after a leak, the heater is as quick and effective as an vehicle I have owned.

Reply to
Tim

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