1993YotaRunner

Yes i have read pages of information about this issue with the 3.slo and overheating. I have done everything that has been mentioned.

Symptoms= i have burped it one thousand ways. tryed the unit that goes into the cap opening, everything. Still overheats like crazy, i have a new fan/shroud, water pump, tryed getting a new t-stat, and then tried old.

The only way it will not overheat is when i took the guts out of my old t-stat and made it hollow so that it is consistantly flowing coolent. BUT it stays way to cold, it only reaches temp when im idleing. At 50 mph it bottoms out on the temp gauge.

I either get HOT or COLD, for some reason i can't achieve an equalibrium. ANY OTHER IDEAS? My timing is good, everything has been done that i can find in the search area on this site.

Could it be that i put an aftermarket exhaust? Got rid of everything from the O2 sensor back.

Any ideas would be good, And yes i am thinking about switching to a 3.4, i have one lined up for 1300, is that a good deal?

And is 450 for a 84 front straight axel with everything attached a good deal?

Sorry about the book, just wanted to put it all in and give alot of info right off the bat.

thanks

Flash319

Where did you get your T-stat? Go get one at the dealer. Aftermarket are ALL JUNK. Also how is your rad? In good shape?

abecedarian

I disagree that all aftermarket stats are junk. I've had mine from Autozone for 2 years now and no issues... but it is a 22re so take that for what it is....

Out of curiousity... what are you using to determine it's overheating? Have you used an infrared thermometer on the coolant outlet? ... are you relying on the gauge on the dash? Have you considered that maybe the sending unit for that gauge isn't working properly?

1993YotaRunner

Radiator is clean, i got my t-stat at a local auto parts store. Im picking up the dealer t-stat tomarow.

1993YotaRunner

Well when the gauge says it is cold, the radiator is touchable, when it overheats on the gauge it is steaming, boiling.

Im sure it is not the gauge, when i would idle when the hollowed out t-stat was in it would heat up to almost normal temp, and the engine would be perfectly warm, and the heater would blow out normal heat.

When i went drove it and picked up speed the engine cooled down to where the needle bottomed out on the temp gauge and and the hot air went away in relation to the gauge readings.

abecedarian

have you replaced the radiator hoses?
the inner lining can separate and cause issues.

1993YotaRunner

This is not my daily driver anymore, i blew the hg last fall and decided it was new truck time.

This is going to be my rubicon trail rig.

And i just can't believe that the t-stat would be the whole problem, ive used the same type t-stat in my beefed up chevy 350 forever and no problems.

1993YotaRunner

I will buy new hoses, but i am sure mine are in great shape. Could it possibly be a heater hose? And if so then why does it not overheat when the t-stat is taken out?

This is just confusing me and hopefully i have a crappy t-stat, but my oe one worked before the hg replacement and after i had a problem.

And there is no oil in the fluid, no fluid in my engine oil either. So i know everything is ok still as far as gaskes go.

I just want to get to the bottom of this. I anticipated more complicated problems to be honest, but this one is stumping me and a cooling system is somewhat simple to diagnose and fix.

abecedarian

if the stat is out, there's not a 'sudden' burst of fluid flow to cause the inner lining to obstruct the passage since flow is constant. make sense?

86Toyrunna

the only thing i can think of is the radiator.. you say its clean.. is this meaning the extierior, or have you checked capacity? have you recently had it tanked and pressure checked. alot of the time a backyard radiator flush wont work if it is really plugged up.

i purchased my 85 pickup knowing that it had a cooling problem. the previous owner baiscally threw parts at it, new watter pump, thermostat, hoses, sensor the whole 9 yards pretty much.. but he never really looked at the radiator. when i got it home i yanked the rad. and took it down to a local radiator repair shop and had them work their magic. when i picked it up they told me that it was roughly 80% clogged. got home put it in and shizam! no more over heating.

hope this helps

Shawn6string

I agree with 86toy... I think its the radiator or a flow issue. The coolant is not flowing like it should...

Junkers88

Had something similar with a big block Ford only I was the one throwing parts in it. Pulled the rad and had it recored and the problem was flat gone.

abecedarian

the problem is, why would it only overheat with the thermostat in? If if the engine ran hot enough to open the stat, the radiator should cool things down enough, because the radiator is enough to cool it down without a stat.

Junkers88

This may sound like a really stupid question but have you been putting the t-stat in backwards?

Shawn6string

?????

1993YotaRunner

Sorry, had to go to a work meeting tonight. But i havn't taken the rad in for repair, might have to do that. But what i ment by clean is from the looks of it there is very little corrosion, and i have flushed it many times.

No i didn't put the t-stat in the wrong way, i checked that first thing. Because i had assembled the front end of the motor at 3 am. Easy mistake to make.

But it is odd that it runs way to COLD when i put in a empty of hollowed out t-stat.

I am going to change hoses, get rad cleaned, and get oe t-stat. If that doesn't work i guess i will do the common fix with any 3.0 problem, PUT IN THE 3.4! too bad i just spent 800 on this 3.0.

1993YotaRunner

Could it be that the way i fill it up and burp it works best with a hollowed out t-stat, but leaves air somewhere when i have a t-stat in??????

Im at a loss other then throwing more parts at it.

vital22re

iTrader: (2)

you said you replaced fan, but what about fan clutch? It should be near full locked if the engine is getting hot. i'd say have the radiator checked at a shop, replace fan clutch if not done yet and get an oem t-stat. or possibly one that runs cooler. and make sure the burping nipple is at the top when throwing the stat in. When you go to fill up the coolant, pull the upper radiator hose from the radiator side and use it like a funnel to fill up the block with coolant. Then reattach and fill up radiator. Good luck

Shawn6string

Try letting it warm up with the cap off, a lot of times there are air pockets in there. As it warms up the air will surface and you will see the coolant go down, then add more. Try squeezing the hoses before it gets to hot, that will help get the air out.
Also once it is warms up you should see the coolant flowing...

934rnr

Did u recently have this engine rebuilt? If it's a V6 it's easy to put the headgaskets in backwards.
That will cause it to overheat very easily and every time no matter what u do.
The coolant passages are in the wrong place so it overheats.
It sounds like your problem.

Also no $450 is too much for a 85 soild front axle. I got mine for $200 with the springs.