Ok, here we go... I bought my v6 3.0 1989 toyota pickup about 4 months ago, the PO stated it ran fine, and it was great. Drove it two months with no problems at all, decided to take it on a little trip, hit the highway for about 50 miles, and then it started overheating on a uphill. Decided it might be the thermostat, bought a oem dual stage from toyota, along with toyota red coolant, and gasket, took the truck in 3 days ago to the mechanic to have it done and ready for a trip this weekend. He started to get into it, and notified me that the PO had not had a thermostat in the truck, he had the housing and that's it. No guts to it, so there was no valve/spring ect. There wasn't any. Restriction there. He then went on to burp the system and it was boiling over at idle and overheating. I told him about the lifting the front end or putting it on a hill to burp it. He said this doesn't need to be done because he has a funnel that brings the water above any low point where air could be trapped so it couldn't be air.

Then he took everything apart again. We put in a new radiator, the old one had deposits inside, and was only flowing 40% so in goes a new one...
water pump was bad needed to be replaced
timing belt was cracked and ready to snap, he replaced that as well
the timing tensioning pulley that touches the smooth side of the timing belt was bad it showed signs of overheating on the puley and timing belt, alot of cracks in it as well
put everything back together and now he's saying its now flowing and there's no air in the system, and there's a clog somewhere.. he's saying it has to be in the block/underneath the intake manifold, and he's going to look into it Monday morning. He's stating its from someone using stop leak in the system which was most likely the PO. But no idea so im not pointing fingers yet.

anyone have any advice of things to check after replacing waterpump, radiator, timing belt, thermostat what to check for now.. what could it be im completely lost..

 

I'm not sold on "burping" the system. That only works if the cooling system has no high spots. Any high spot in the system, such as and idle speed control valve, throttle body,heater core ect, and it will still have air in the system. I think any decent/reputable shop (including body shops) will have a vaccu-fill. Take it to a shop that has one and you'll be sure its good. If it still doesn't have flow, your looking at a blockage or something else.

 

I was talking to him about it and he was saying they filled the area behind the thermostat with fluid, with some tool/device. He's convinced its not air.

It definetly is a reputible shop, and repituble mechanic. He worked for the dealer for years before opening his own shop when the local mitsubishi dealer closed down.

 

ok. Using a funnel seemed a bit...crude and ineffective.

Play along with me on this thought. A common mod on snowmobiles is to gut the thermostat and re-install (for some restriction) and put a block in the rad by pass hose. This forces antifreeze through the rad all the time. It means you have to let it warm up longer but after that all your antifreeze is being cooled before entering the engine again. Giving you a cooler running engine (or so theory says) Maybe this is what he did to your truck engine. If a normal thermo was re-installed and the bypass was blocked, it would cause it to overheat quickly as the coolant won't flow at all.

 

So check the radiator bypass hose? Where is this located. Sorry im a new to this, and quite frustrated

 

^I've never had problems bleeding coolant systems using a funnel and coolant above the highest point.

I have seen coolant tubes and passages blocked by leak stopper additives though, if the early 3.0's were the ones known for head gasket issues it seems highly possible someone added leak stopper to the system.

 

Isn't the purpose of the dual stage thermo to allow water flow at all times through a smaller opening?

 

Your engine won't have a rad bypass hose. Thats a snowmobile thing. It will have a passage in the block that will perform the same function.

And like said above, that leak stop can clog stuff bad. (such as your rad that was plugged up)

 

Does the heater work? Good and hot?

It is rare but possible to get blockages in the intake manifold ports and block/head water jackets....

I would suggest flushing the system the way it should be done then bleeding it naturaly...

1 Drain all engine coolant from plug on bottom of radiator.
(Because thr thermostat is located at the bottom radiator hose its much easier and recommended to fill the engine with [coolant/water] at the upper radiator hose. Remove upper rad hose and fill directly into hose this will fill the engine faster and better.)
(Once filled replace upper hose to correct postion)
2 Start engine and fill radiator with water remembering to leave the radiator drain plug out.
3 Put a pan/bucket to catch coolant/water from drain plug.
4 Keeping radiator topped off with water with engine running while everything is flushed out the radiator drain plug.
5 Keeping the heater on high as well during this process.
6 Continue this until its just 100% water running from the drain plug.

If this does not work then the engine will need to be disassembled to find and correct blockage....

They do make some cooling system cleaners... they may work well but damage seals and components.... use at your own risk...

 

The radiator had build up that looked like calcium deposits or little rocks, maybe from using hose water to fill the radiator? Ionce again PO)..... im just los5 and I kind of feel the mecanic is starting to slightly hit a dead end and doesn't know to continue, or if he is leaning twords convincing me to try to huck the truck to someone else with the said problem still existing. He started he will try to look into passages or coolant tubes Monday morning. If it is stopleak in the block somewhere, is it a lost cause? Do I need a new block; or is there ways to come back from this problem? Something to disrupt it, and clean out the stopleak?

 

those "little rocks" you speak of are from a stop leak solution that was added. People use all sorts of stuff. Some add a fist full of sand, some add pepper, I've heard of people cracking an egg in their rad to fix leaks too. The idea being the larger particles clog the opening of the leak and its "fixed" except the sand in the stop leak will build up in lots of places and essentially polish your cooling system...including your water pump bearings, impeller and any gasket that touches the cooling system...which is likely why you had to replace the water pump.

I can't see the stop leak causing a total blockage of a passage but you never know. Crazier things have happened. Its literally fine sand in that stuff, I don't see how it would build up enough.

If it is a blockage in the block, depending where it is, it should be possible to clean it out. I've never head of it being done before. It might take more money than your willing to spend though. But thats a worst case senario.

 

p.s. this is info on a dual stage thermo including a picture which helps.

https://www.yotatech.com/forums/f2/d...-thermo-67562/

 

A failing fan clutch will cause the motor to over heat. You may have him try the newspaper trick just to verify its good.

 

vital, your right, but a failing fan clutch will not cause the coolant to stop flowing.

 

I know this is remedial but was the thermostat put in properly??
When installing the thermostat the little pin hole with the jiggler in it needs to be facing forward in line with the hose or it will still Overshoot or be very slow opening. You can' t just pop in the thermostat however and expect it to work properly.

 

I am dealing with the same issue but I haven't replaced the radiator yet. I started a thread to see if I could get an upgraded radiator from a different vehicle. I just hope it helps. I was thinking about doing a flow down test by just backflushing from the top hose down. I will be replacing the thermostat with an OE as well as replacing the radiator with one I found today at PICKNPULL. gotta love 50% off sales

 

Yepp, FC is good and works

 

Good luck to you insolving your problem, I think only the hand of god could save my vacation now, as I was supposed to be at the dunes already.. but I think its a lost cause, so im just hoping at this point im not starting to get to too stoked, cause everytime I walk into the shop were spending more $$$$$$.. hopefully im out of this shop with under 1k..
and the mechanic stated that it loos as if one of the PO had done headgaskets/valve cover gasket, but one of the VCG is slightly leaking
/endrant
thanks guys for all the help so far I really appreciate it

 

Turns out we traced the problem back to the PO using STOP LEAK through the cooling system. The motor is getting ripped apart, and rebuilt completely. Using all OEM parts, annd setting me back a preety penny of 2200$ with new waterpump, radiator, hg, valve covers gaskets, timing belt, vales, everyyythings getting redone, and the mechanic is going to gaurentee the motor for 2 years. That's better than anyone else I asked, everyone else offered to warranty for 12k/12 months. Positive side is ill have a fresh 3vze. Then next step will be to SAS this summer hopefully, but it might have to wait till next summer so I can gather all the parts, idk how long its going to take to get everything together

 

** the stopleak clogged up and made deposits in the water galleys and jackets...