headgasket

Hey Yota Techers:

My friend's 89 pickup 1/2 ton extra cab started overheating. From experience I pulled his dipstick and viola the milkshake symptoms. We pulled it into the garage and have it halfway torn down. He then tested the old thermostat and it will not open even in boiling water.

Our question is how often does something like this become the cause of his gasket failure? No other leaks from radiator or no white smoke in the exhaust.

Does the head need to be milled flat. I know on v-6 3.0's that is a precaution I do.

We can get a manual from the library and found the online link at tulsa university so think we'll be ok. Just trying to trouble shoot the cause.

We'll also replace the timing chain, water pump, etc.

corax

I assume he didn't notice it overheating, or did, and just kept driving? If you overheat an engine with an aluminum cylinder head, you'll very likely have problems with cyl head warpage. Find a striaght edge and check the cyl head for warpage or take it to a machine shop and have them check it, most likely it'll need to be machined.

abecedarian

a stuck-closed tstat will cause overheating and a blown hg. a blown hg can cause overheating and a stuck tstat as well.
if the gasket failure occurs between a water passage an oil passage, you'll get water in the oil and no water/steam out the tailpipe.
as mentioned, get the head checked for warpage. it's very possible it's not warped though since it appears it didn't overheat enough to blow out into a cylinder.

frannie

I just drove my 89 22re 2wd pickup across the country and it started overheating now that i'm in the desert. sometimes it's fine and it doesnt and sometimes i just drive 15 min. down the road (the road being steep and windy) and it starts to overheat. i always shut the truck off let it cool, i have had to add water at times. so i took it to a mechanic and he didn't do any tests or check the thermostat he just said right off the bat that it's my timing chain cover wearing through and messing with the water pump. i've decided to check and replace the thermostat first. there's no white smoke and no water seems to be mixed in with the oil.
does it seem likely that this is a timing chain cover issue or should i continue on my coolant system overhaul?
i've never posted on here and i hope i put this in the right place
ps i know i shouldn't keep putting water in to the radiator just had to do it a couple times cause i had nothin else
any info would be great

abecedarian

Timing chain wear to the cover is obvious: when it overheats, it's because the coolant went through the cover and in to the crankcase, and then your engine oil looks like chocolate milk.

Your thermostat could be sticking. If things are fine sometimes, and at other times you run hot even though it's the same temp outside I'd suspect the t-stat before anything else.

shallwminded

next time it gets hot lightly touch the top rad hose and see if its hot.if not hot its thermostat.if its hot probably radiator.hope it helps kenny

frannie

changed the thermostat and cleaned off a lot of mud caked to the radiator with a soft brush and did a coolant flush. seems good, just drove for 24 hours pretty much straight.