Ok i had issues with the headgasket about 1.5yrs ago and fixed it by gutting the thermostat. This worked great except for the truck wouldnt heat up in the winter very well. Now i was driving it yesterday and it heated up and i shut it off right away after i saw the gauge going into the red. It had zero coolant like it had just pushed it all out the overflow. I added coolant and it seemed ok for a while yesterday. Now it will overheat and push all the coolant out withing a few minutes of highway driving. I know the thermostat isnt blocked because its hogged out. I know the waterpump is working because its steaming hot when it overflows. Now why would it be pushing the coolant out. Lets say its a headgasket. why isnt the pressure from the leak just venting to the air vs pushing the coolant out with it. The hot air should rise up into the coolant overflow and just vent it shouldnt push out the coolant. This is my beater deer hunting truck and i drive it to work a couple miles a day. Is there a stop leak that guys have been successful using in our trucks. I read k seal and a couple others but wanted to hear from successful guys and gals. thanks Kevin

 

If this is a D1, it has a copper & brass radiator. You can remove it yourself, take to indy rad shop, and have it acid boiled and calcium rodded out, about $70 near me at a small place that does tractor and heavy equipment radiators. Your cooling system is clogged up, and has been hidden by running with no stat. That keeps temps at 130 - 140 F (when I tried it).

If you don't flush the radiator, most stop leaks products will seal up the lower rows of tubes that are full of gunk and barely flowing. Then, with 1/2 a radiator, you will overheat more.

If you are going to use stop leak, the Kseal has the minimum quantity of material to be left over and try to clog things.

The physics at work involves steam - which increases volume as it expands - and pushes the coolant out of all available spaces.

So can you try stop leak? Yes. If your coolant system is not in great shape, it will make overheating worse.

Should shut off before it gets to red. Way before. When mine is just above mid point, it is already 236 F.

 

It's a disco 2. I just am not sure if it's a hg issue. I do alot of drag racing and have nuked many headgaskets. They have all milkshaked the oil. My oil is clean. How can a headgasket issue not let oil and coolant mix together. It can't be a one way deal. Thanks for any info.

 

ok. Then aluminum radiator - so you may have to replace radiator, if it had dexcool in it there could also be sludge. With the opened up thermostat, did you close off the top bypass line, might add to the problem. See attached coolant flow. Pix of external HG leak, could have made you low on coolant, down the back of engine (maybe even just valley pan gasket), then boil over and overheat.

Compression test? Coolant pressure test? Borrow testers from auto parts store.

 

So your not thinking head gasket. It's been replaced about 30k ago.

 

You need to do a coolant pressure test to verify a leak.
I would get rid of that t/stat and go to one of the newer after market units that will flow more, run cooler up allow the ECU to go into close loop for more power and better mileage.

 

I am borrowing one tonight. Do I need to refill the coolant or leave it a little low to test. I would assume if it was leaking gases into the coolant system lime it looks like it is then it should show up pretty quick. I did it when it was overheating before and the color didn't really change much from the blue. Thanks for the replies. Where can I get the newer style t stat

 

see Installed 180f thermostat in place of 192f thermostat - Land Rover Forums : Land Rover and Range Rover Forum. You could have an external leak, down back of block, etc., that gets burned off. No white smoke from tail pipe, no milkshake oil. But good coolant loss, and in a hot environment you may not notice. Then truck overheats (low coolant) and boils over (steam). An HG can leak into air, into cylinders, into oil, or all three.

 

I got to dig into it a little. First thing I did was try to open the overflow cap. It still had tons of pressure in it. I mean had to go really slow to get it to not burp out all the fluid. This is leading me to think radiator issue or something other than head gasket. If it was the head gasket it would have bled the pressure off while it sat. It sat for 18hrs. There is no way it would have held pressure that long if there was a way to bleed it off Aka headgasket. I basically pressure tested it for a day if you think about it. I'm still going to check the overflow for exhaust gas.

 

Wrong, the radiator, although possibly restricted can not cause pressure to build up and hold it. Go do the coolant pressure test with the system full of water/coolant, if it fails and you want more proof then do a chemical block test for exhaust in the coolant.