brettb

1995 T100 3.4 6cyl manual with radiator/coolant overflow problem

just bought the truck.... have papers for rebuild 15,000 miles ago 11 months still on warranty but its in CA I'm in CO.

problem is pulling up hills (mostly) coolant overflows out of overflow resevoir tube...and radiator was boiling/gurgeling and temp. gauge was rising toward red

after flush and replacing 2 hoses, radiator cap and t-stat and refilling with coolant temp gauge now holds at straight up and still overflowing out of resevoir... don't really hear the boiling sound...

I was told it was a "heavy duty radiator" cap was shot and t-stat looked 20 yrs old! replaced them and hoses as they were old as well... fan appears to be working as well but have not checked while hot? this is my first toyota so new to engine etc. valve covers are leaking as well... any advice or help would be greatly appreciated? was wondering about coolant temp sensor or anything else that could cause this!??????

rworegon

Are you burning coolant through the exhaust i.e. white smoke? How does the oil look? How did the coolant your drained out look? Sounds like exhaust gases are pressurizing the cooling system.

brettb

coolant looked nasty had some sediment in reservoir...
oil looked great but he had just done an oil change before i bought it?
exhaust looks good as well..
engine pulls strong... the hoses were collapsing when turned off and began cool down

rworegon

Is the overflow reservoir full of coolant when the coolant is coming out the overflow tube? Anyhow, take the tubes off the reservoir and make sure they are all clear of blockages. There may be a vent hole on the reservoir cap too.

brettb

yup the reservoir is full when hot....

250000_yota

Brett, I saw you were in Colorado. Where exactly? If you don't get anywhere with the overheating, I might be able to help if you were close enough.

brettb

Georgetown... 40 min west of Denver

rworegon

What's the level in the reservoir and the radiator when the engine is cold? Is the coolant being pulled back to the radiator?

It may be that it's just time to replace the radiator. Nasty coolant and sediment in the overflow leads me to believe the cooling system may have been neglected and the radiator may be partially plugged.

There is no mud, etc. in the radiator fins?

brettb

radiator exterior looks clear I am checking the reservoir tonight when I get home to see the level when cold..
when I flushed the radiator it seemed to flow the water right thru.... is it something that if clogged its more obvious when under pressure?

250000_yota

How did the coolant from the first flush look? I know that with the last engine I helped rebuild, the coolant looked like crap after the first 1000 miles, from all the left overs in the block. I wouldn't be suprised if some of the crap from your build clogged up the internals of the radiator. It very definitely might be time to replace the rad.

brettb

so glad you guys are leaning toward radiator and not head gasket!
just bought the truck.... coolant had sediment for sure... flushed it out with water ran it for a 5 min ride then handed it off to local repair for a "BG" chemical flush... a little dirty from that flush as well.... trying to figure out how if the radiator is clogged why the overflow res. would overflow?

rworegon

Well, HG is certainly in the mix........but, being it only seems to happen under high load conditions tilts the needle away from the HG a bit. The HG and it's related symptoms would likely being under most all conditions.

Do you know when the water pump was last changed? The water pump is driven by the timing belt. I had a situation where the timing belt stretch and a weak hydraulic tensioner was causing the water pump to be inefficient. Changed it all out and temps dropped from 203f to 191f around town and on the highway.

brettb

water pump was supposed to be replaced when rebuild was done 15,000 mi ago....
according to paperwork

rworegon

Here is the thought: the passages in the radiator are partially plugged causing the coolant to not be cooled properly leading to overheating and boilover into the overflow.

You are using the stock temp Toyota OEM thermostat with the jiggle valve pointed down? Also, a Toyota radiator cap?

rworegon

Since you just bought it, it makes it tougher to know if this is a new or existing problem.

Are you sure all the air is out of the cooling system? Get the radiator cap at the highest point, remove cap, start engine, turn heater on high heat and fan on high, and bring engine up to temp.....the air bubbles will belch out and add coolant as necessary.


https://www.yotatech.com/forums/f2/3...gh-rpm-247758/
https://www.yotatech.com/forums/f2/5...easure-249481/

brettb

i will double check all air is out... doesn't hurt to do it again with maybe a more extreme able
.... I believe it is existing based on the amount of residue under the hood.... the P.O. did mention the upper radiator hose came unhooked (I'M NOW GUESSING BLEW OFF???)
hmmm. its supposed to be an aftermarket radiator... sorry this is my first toyota after 3 F150s leading to disaster!!! not really familiar with these procedures...or engine

rworegon

Uh oh, that hose coming off may be the HG gas pressure issue. Take a good whiff of the overflow tank with the lid off...do you smell exhaust gases.....sometimes you can.

Are you using the search function here? There is tons of great knowledge on this site.

brettb

yup I searched for a long time today.... maybe searched poorly but found stuff not duplicating my issue.... mostly leaks or overheating at idle or stop & go.... things of that nature.... as well as fan clutch issues and coolant temp. sensor breaking? even clogged tubes? from stop leak...

whats the damage$$ for a new head gasket? I understand the process and won't be able to do it myself... I work 60-80 hrs a week....

rworegon

Before you jump to the HG, a coolant system pressure test and a leak down test should be performed.

I'd order a free kit from Blackstone and do a Used Oil Analysis to see if you have coolant contamination in the oil....see my post 78 and 79:
https://www.yotatech.com/forums/f2/r...35/index4.html

There are still some diagnostics to go through before the HG is condemed.

Maybe one of the CO guys will chime in with input on a shop recommendation in your area.

brettb

that would be great to find a reliable shop not wanting to get taken hard for this....

how long might i drive it ? just wondering how long oil contamination takes? I've got maybe 100 mi. on it with the new coolant and sounds like oil change was less than 100mi as well... my local shop thought the oil looked good? but not convinced on that reliability for sure... I will redo the air tonight or tomorrow after work and check oil and res. for contamination.....
water pump? is there a way to test that or is it of no concern? thanks for your help!