OK, First I hate water cooled vehicals, That aside... My '82 toy radiator seems too hot and gauge is straight up, years ago it used to be at about 1/3rd, going up hills needle gets close to red.

What i've done so far; cleaned radiator, water flows through it like flushing water down the sewer, got a new pump as there was a leak from seal. New T-stat, 190deg. replaced sensor that was cracked and leaking. Fan clutch is working fine and not very old, pulls firm when cold. Belts replaced a year ago and not loose. New radiator cap. Whats left? Could there be a blockage in the block and if yes how to clear it? I hear this happend to another and found a piece of rubber hose? but how to remove it if thats the problem...

Note; When the caps off and warmed up I look in the radiator and rev it up but see no flow, as revs get higher the coolant level drops and back to idle the coolant rises to top of opening??? Like the pump cant get enough water and creates suction is what i'm thinking....

Dont say radiator cause a fire hose couldnt make it back up its so clean... just saying THANKS FOR ANY HELP

 

You pulled the core out of the radiator and cleaned it using the rod technique ??

Just how old is the radiator??

You also used a infra red heat gun to check for blockages ??

 

Dont have a IR heat gun, but i'm going to borrow one to make sure...

age? maybe 10 years? is this telling?

I figured if i had to rod it might as well get a new one, there not that pricey

I cleaned the radiator out of the truck. Used muriatic about 4x (at least 24hrs total soaking) and flushed each time, then baking soda. We have good water pressure and water would come out as fast as putting it in no matter which hole, as i flushed from all three holes and watched to see it flowing to the sides not just in one spot. Can a radiator flow water that well and still be an issue with flow? Hard to imagine but might be something weird going on in there? I think i should see water flowing across the top tank with the way it did with garden hose even if there were some plugged tubes? its like a dead calm, makes no sense to me....

 

Hi
would suggest blockage in engine block. remove thermostat and top hose and run water from bottom to top then top to bottom. engine can be run for short time while flushing as you will have water going through block.

 

Ps sounds like water pump is in good working order. just a final thought how did you bleed engine. posted else where on yotatech it is recommend to get front of truck as high as possiable off the ground so that rad cap is highest point.

 

Thanks, I did see those threads on bleeding and followed instructions. Also while the cap was loose went up the steepest low gear street near me very slow.

 

Dont you mean remove bottom hose also??? or not???

 

Err yes remove bottom hose.

 

On low gear hill very slow might be to slow. You need a few revs on engine to push the water around. When truck is in level ground take rad cap on and manually increase revs by moving throttle lever and see the difference. Yes cap on loose going up a steep hill is good idea. Doing a bleed today on mine as 3 hose clips have been replaced. Never took hoses off just opened jubilee clips up and rejoined around hoses. Lazy yes but a 40mph wind and 7" rain in 16 hours was a deciding factor. No wind today and a chance of rain shower means i can get to check and do it properly.

 

It was reving pretty well but meant slow as staying in low gear, dont think theres air trapped plus I had replaced the sensor and just coolant as I screwed it back in. Bad weather is always a pain esp using tools in cold but we're in the 80's here in so. cal. for a couple days.

Note; I need to first finish repairing the recovery/washer tanks. They were cracking at top and 1" down so sanded and used a thin layer of regular epoxy to fill cracks then nylon cloth with epoxy gel for a solid cover seal. Was lucky to be able to reach inside to back a hole with tape and the gel works great to fill. Next a sanding and second coat of gel. Looks ok with second sanding and low levels filled with putty knife so no paint needed, good enough for everyday driver.

 

Glad you are progressing. Repairs look good. Me flushed my engine out. Hosepipe in to heater pipe bottom of block top inlet on radiator and top of radiator through cap hole. Two hours later still getting discoloured water out. Lawn is now same colour as dirty water ummmmm see how much grass dies. Filled block through heater hose with front on wheel ramps. Need to get front higher as still got a very small airlock but vast improvement on before. Need another 6-8 inches of height. Jack wont go that high.

 

Hi
Had brainwave while walking dog. Have loads of large flat stones. Will see if i can build a ramp out them to get height need or buy a bleed valve as fitted to renaults.

 

i never worried much about the air bleeding as it usually bleeds it self out in time esp if you have the wiggle-pin on your T=Stat. I think the extra steps help insure its bled right away though?

 

Ok thanks for the tip. I always thought you had to bleed out every bit of air before front end was lowered to ground.

 

Heres a link to some ideas, must be more links but good things to consider, like make sure motor is fully warmed up and turn heater temp on for flow through heater core. "Burp the cooling system", lol

https://www.yotatech.com/forums/f116...estion-278987/

https://www.yotatech.com/forums/f116...m-3vze-194704/

 

I'll chime in on a couple of thoughts on your issue.

1-You should not see flow through the radiator until the engine is up to your thermostat temperature - It likely won't burp much either. So if you have a 190* thermostat (Factory is 190* - I prefer to run a 180*) then the engine will need to be up to 190* before you will start to see flow through the radiator. I would try to snag an IR thermometer if you can so you don't have to rely on the gauges so much to determine the temperature.

2-Given the info above, You CANNOT completely burp the cooling system until the coolant temp is up past the thermostat opening temperature. Start the engine completely cold with the cap off ( so you don't burn the bejesus out of yourself) and run it until it is up to full operating temperature while adding coolant as it burps. Positioning the truck slightly up hill isn't necessary - coolant (and trapped air) has to flow up AND down throughout the engine so the angle of the vehicle isn't going to help force the air out anymore. It'll still burp on flat ground since it is the actually the flow of the coolant that pushes the air out, not gravity or rising air. As long as your truck isn't upside down, it will burp. The only real need to park uphill would be to initially fill the coolant so that it helps drain as much coolant as possible back into the engine, but even still that doesn't matter since you can add more coolant as it circulates and burps.

3-Make sure that you have coolant in the reservoir when the truck cools off. If you notice that there is coolant in the reservoir when it is hot, but none (or very little) when it is cold then that means your coolant system is likely sucking up air after it sucks up the coolant in the reservoir when the engine cools so its basically injecting air back into your cooling system the next time you start it up and you will need to burp it again. I like to fill my reservoir just shy of the max line before I burp the system and then make sure that it is properly filled after the engine is burped and has cooled.

4-I also like to filled the engine with coolant before I fill the radiator. With everything properly plumbed, I remove the thermostat and fill the engine with coolant through the thermostat housing hole in the intake then I reinstall the thermostat housing and fill up the radiator. This way I am filling the engine from the top down instead of the bottom up. When you fill the cooling system through the radiator, the coolant drains down through the radiator and works its way back up through the engine (basically the reverse flow of the operating circulation) since it can't flow through the closed thermostat - you also trap more air that way as well.

5-Use the premixed coolant - not the 50/50 stuff you have to add water to. The impurities in your tap water will corrode your engine and radiator. I use the Toyota Red premixed coolant in all my Toyotas. It costs a little more, but I change the coolant less often and it always comes out nice and clean. I just changed the coolant in my wife's Camry after about 50,000 miles (she puts about 20,000/year on her car) and I could have easily let it go another 20,000 miles with no problems. If you do end up using 50/50 coolant, make sure you use distilled (that's distilled, not filtered) water and pour it directly from the jug into the radiator.

If you think that you may have a blockage, I would start by removing the thermostat and running the engine. At least that way, you can eliminate the warm up process and you know that coolant should be flowing through the system as soon as you turn the key.

Sorry for the rant/novel, but I hope this help you out!

 

Hi
Thanks for pointers. Did raise front of truck on stone slabs not concrete with wooden ramps. Then ran engine for 30mins giving all the hoses a squeeze. Started at bottom hose then heater hoses last top rad hose. Got air bubbles every time second time round could not feel air rattling on heater hose. Always kept eye on rad level. Let it cool for a couple of hours. Had to top up overflow bottle with a pint of coolant. Ran engine again went though same hose squeezing sequince. No air bubbles this time. Fingers crossed ive got 90%+ of air out. Need to go out tomorrow so will take it out on short test drive of 10-15 miles. Should throw up any issues. If this fails then i've found a coolant bleed valve to put in heater hose to help air out. These are very common on european cars.
One thing i have noticed is my fan is running in resitant mode all the time. Used a rolled up newspaper to test better than a leather glove on hand as i like my fingers.

 

Hi
after doing 100 miles today and found a very steep hill to drive up still have an airlock. so on to plan B which is to fit a bleeder valve in heater hose £7 delivered as used by caterham road cars to aid bleeding on heater matrix.

 

I just use a tee in the heater hose it is the highest point .

Fill the radiator as the coolant goes in it pushes the air out.

It works for me.

 

Chefdave I'm going to do as you did with flushing the block as soon as it drys out here. I removed the recover tank to fix and had the coolant level down about an inch for 5 days and still see no real flow. I suppose theres just enough flow to keep from over heating

Kawazx, I would also prefer the 180 deg T-Stat but with the 180 in the mountains it wouldn't keep it warm enough inside so trying the 190 for now, could be scale in the heater core perhaps? Anyone else have problems staying warm near or below freezing with a 180 T-Stat.....