# Overheating on 1988 chevy PU??



## MadMax45 (Oct 30, 2008)

Hope someone knows car engine here!! I just bought a 1988 chevy PU and it wasnt blowing hot air when heater was on! Well I thought well thats simple fix, I will change the thermostat! Well I when changing it I found that there was no thermostat in it at all! So I put a new one in and the damn thing started overheating! The temp gauge never moved before! I doubled checked to see if I put it in right and I did! Never seen anything like this before! Does anyone have any advice? Thanks MadMax


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## Guyzer (Jul 3, 2004)

1 ) Check to see that the water pump isn't seized. If it isn't then....

2) The rad is probably full of crud and plugged up solid.


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## Knotbored (Jun 5, 2004)

Air can get trapped in the line and prevent the thermostat from sensing its supposed to open. An old trick to get the air purged is to force the thermostat spring open (with thermostat out of the car) and put an asperin tablet to hold it open. Install the thermostat and immediatly start the car. The water runs thru until the tablet is disolved then water has purged the air out.
If the car ran cool with no thermostat but runs hot with a thermostat then logic says water isn't getting past the thermostat.


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## JohnWill (Oct 19, 2002)

Another issue here is the block cooling passages could be blocked. I've recently seen this on a friend's Ford Explorer that was about 10 years old, very ugly!


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## MadMax45 (Oct 30, 2008)

Thanks everyone for your help! Im leaning more towards Knots idea since the truck didn't run hot with thermo out! I have heard of alot of trix before, but never heard about the one you have Knot! The problem with that trick on this truck, is the main bracket holding the tention belt pully is connected to the bolt that holds the thermo housing down! So, by the time I get bracket and belt back on, it will probably be closed agian! Is there another way to purge it? Also is it possible that it could have had a weak water pump or part clogged radiator is why the thermo was out? Anyway Thanks again, Madmax


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## wacor (Feb 22, 2005)

if you get an aspirin that is coated I doubt it would dissolve that fast.


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## mrss (Jun 13, 2007)

New thermostat and not one from the junk box, although tstats like to fail in the open position? Also, you mounted it so the body with the cylinder points toward the engine?

I betcha it's more likely a clogged radiator than air that you didn't burp out. Otherwise, why was the tstat missing? Answer - so he could sell the truck.

Luckily, most radiators come from China these days and don't cost much more than 125 bucks.


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## Guyzer (Jul 3, 2004)

I hate it when I misread an original post. Sorry about that.

I still stand on the bad rad though. I'll betcha it's plugged. Remove it and take it to a rad shop. They can do a flow test and that will tell you for sure.


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## Knotbored (Jun 5, 2004)

The asperin won't be in water until you attach that last bolt and fill the radiator, although using a coated pill also sounds like a good idea. How long are you goinng to keep the truck?-Maybe an investment now in a radiator is a good idea anyway-and a set of tires-why leave those untill you sell it to the next guy?


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## MadMax45 (Oct 30, 2008)

Yeah, its looking towards the rad, so I will be taking it out and taking it to the shop to get it tested in a couple of days! As far as the truck goes, you probably are right about the guy wanting to sell it and leaving things as is! That wouldnt even bother me if the rad was bad, the prob is that I ask the guy let me know about everything he knows is wrong so I can fix it! The price I gave for it, I would expect to fix some things, but just pisses me off when im lied to, then I end up with something like this, where I waste time looking for a solutions! Another funny thing the damn truck has 4 brand new tires on it!  go figure!!! Hey guys thanks for your help, I guess I was hoping for a quick fix! Laters MadMax


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## daniel_b2380 (Jan 31, 2003)

is it actually over-heating, or just the gauge?
[hand on the radiator?],
.
do you have any leaks?
summer to winter climate changes,
need to check clamp tightness,
pin-hole in radiator?
freeze-plug leaking?
is the vehicle parked where you can see residue,
like on concrete or asphalt?
.
should be able to see some indication of the radiator condition,
when you have the cap removed,
.
why not check to see if the thermostat is any good?
just being new isn't saying it isn't defective,
old school:
put the thermostat in a pot of water on the stove,
bring to a boil, [212F = boiling],
thermostat is probably 180 to 195F,
[newer vehicles will be higher],
.
how new is the drive belt?
how tight is the drivebelt?
'older' or loose drive belts can 'slip' at high-way speeds,
to tight can prematurely wear the bearings,
.
do you have the 'green' anti-freeze?
or the 'purple' stuff?
the 'purple' anti-freeze is really for aluminum engines,
your '88 should be cast iron,
AND, 
when the 'purple stuff gets older,
looking in the radiator,
[with the cap off],
can be a gruesome looking mess,
.
NOTE:
goes without even saying,
NEVER REMOVE A RADIATOR CAP WHEN VEHICLE IS HOT!!!


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