radiator reseve tank bubbling

[superninja2]

I have driving my 1991 FJ-80 Series a few times now and it has overheated. The engine was very hot on two occasions. I pulled the radiator, sealed the leaks, and flushed it. I also flushed the system by pulling the radiator plug and the engine block plug. It still leaks a bit from below the radiator so It probably was not sealed correctly. Also, the plastic reserve radiator tank has boiled on each occasion. My mechanic says we need to replace the head gasket seal so that it will not overheat. Will this fix the problem. I will also probably get a new radiator(The cheap Chinese Version) as I am in Baja Mexico and it is hard to find oem parts down here. Especially after the Hurricane Odele. Any suggestions and insights would be greatly appreciated! thanks

 

[frank rabbets]

Changing the head gasket is a big job. I would test the engine water for combustion products to confirm the head gasket is faulty. Most good garages here can test the water. If the water is clean perhaps the thermostat is seized shut. You can test for water flow by warming the engine up without the rad cap on. If you give the engine a good rev up you should see water swirling in the rad top tank and the water level rising up and down.

It will be interesting to see how you get on as I think it is an unusual problem. Diesel or petrol?

 

[Dave2000]

Do as Frank suggests and check the cheap stuff like thermostat working. It is possible the vanes in the water pump are broken (plastic version) or corroded on a steel version. Is it possible that the engine is simply very hot from the fan not working correctly? There has been a lot of viscous coupling issues as these cars are not getting any younger check that as well.

regards

Dave

 

[Bat21]

Is the water in your header tank (plastic reserve tank) clean or is it dirty/oily/smelly?

Carry out this simple test. With the engine cold (first thing in the morning) loosen the radiator cap (not the one on the plastic tank) to release any pressure, and then refit. Start the engine and run it for 30 seconds (no more). Now release the radiator cap once again. If you have ANY pressure there when releasing then you have problems.

I had exactly the same problems as you and it turned out to be a cracked cylinder bore

 

[frank rabbets]

Yes I forgot that cracked block. I can't see a head gasket failing. BAT do you think your crack was caused by overheating sometime? I've done 4,000 miles in mine now and used no water so those rusty stains you pointed out weren't cracks thank goodness.

 

[Bat21]

Not sure which came first in my case Frank. Mine clearly had problems before I bought it as the header tank was full of sludge when I looked even then. Either the crack caused the over heating or, the over heating caused the crack. Oddly mine only ever used water in very hot conditions. I have now done over 20,000 miles since the engine rebuild and it has used NO coolant at all, that includes 3 Morocco trips.

Yours sounds like it is going to be fine now too

 

[pberrey]

Superninja, boiling coolant can be caused by a number of things but it's mainly a stuck thermostat, a blocked radiator or a failed water pump. The problem is if the engine has really over heated it could have warped the heat so changing the head gasket without checking it is flat and skimming it if necessary is pointless. It will just blow another head gasket. If the HG has gone you will also see white steam coming out if the exhaust which will smell sweat due to the glycol in the coolant. It's an easy test to check the coolant for exhaust gasses and an immediate build of pressure in the coolant system would indicate either a failed HG or a cracked block as said above.

None of this is terminal but it could be costly worst case. Best case is it's a stuck thermostat which is a £20 part.

Good luck


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