Hi,

I just purchased a 2wd 1986, A/T, Toy Pu for a daily driver. It is a little low on the cool points scale but it is actually a kick to drive. Unfrotunately it is having some engine heating issues. So here is the deal...

I just replaced the Head Gasket, so i know the thing isn't leaking coolant internally. The oil is straight black, and it doesn't look like a chocolate milkshake so I am pretty sure the head gasket is good. It also has good compression. I am running a 195 degree thermostat.

Here are the symptoms...

I reassembled the engine and got the thing tuned and running. The timing seems to be correct, if anything maybe a little too retarded...hahahah. The fluid level is correct. The spark plugs are pretty good color. The problem is
the truck heats up in about a minute and a half. It will sit at halfway on the scale and then just shoot up to right below the last white mark before the H. The test runs I have done have been at night in approximately 70 degree weather. I don't really know where to go from here.

Hopefully somebody can tell me something I haven't already thought of.


Thanks for the input,

Jon

 

It sounds like either the thermostat isn't opening when it's supposed to or that you have air in the system. Did you make sure it burped when you did the head gasket? You could either test the stat in a pot of water on the stove with a thermometer or remove it and see if it makes a difference. Could it be installed backwards? I know it sounds stupid but I've seen it before so I have to ask.

 

I can't find anywhere what the stock thermostat temp is. The truck runs "hot" with respect to the gauge but it really doesn't push past that point. I am wondering if maybe my gauge or sensor is jacked up.

 

When you notice the temp guage shoot up to hot.check to see if your heater is blowing hot or cold air. if it is cold your thermostat is sticking an should be replaced Also you'll need to burp the radiator by taking off the cap an let it run till you see the water start burping out,Then replace cap.Also check that the hoses arent clapsing when this happens.If these things check ok then you need to look at a bad water pump or radiator clogged

 

Also - Id would view the stock guage sensor with a mite of suspician...

I have an autometer "mech" temp guage" hooked up - much better.

I had a case where the dahs guage was doing the same thing. A glance at the Autometer guage showed that the dahs guage was wrong...

 

my dash gauge quit working but it still moved like i would think it should but one day it shot up all the way to high less than a mile away from my house in cold weather, at that point i realized it was proally broken. after my temp gauge started bouncing up to my music i decided to install a new mechanical gauge for $15 from shucks and it works great. even with my old water temperature sender removed and the wire just hanging there my gauge still move up to where it should be, so it made me wonder how long it had been broken. a minute and a half is awefully fast for an engine to overheat so i think you might have a gauge problem