FJ62 Radiator leaking or burping after cooling off (1 Viewer)

[ColnagoNH]

Sorry new guy card! I recently bought an '89 FJ62 with 240k miles and am in love. It is my daily and slowly working through issues as is pretty clean but has its unique little things I am slowly finding. My current issue I cannot figure out is loss of coolant but was not seeing any drips so was thinking head gasket but no white smoke just some minor damp from exhaust which seems normal to me and also no cloudy oil or bubbles in reservoir. Also is rock solid on engine temp but have had a bit of issue keeping my transmission from overheating. Have some clunky shifting and other tranny issues working through so have been thinking not a coolant/radiator issue.

After I flushed and filled it got very hot very fast on initial startup so shut it down quickly and seemed like I had an air lock. spent a bunch of time burping and even ran it while on incline for 30 minutes while watching coolant level and keeping topped off. Seems like there may be a leak in the radiator or a hose that happened when it overheated on initial startup as I will get some drips when cold but then when it heats up no drips, rock solid on engine temp and runs great. Issue is I keep getting a burp or something overnight after the engine has completely cooled down as in the morning I will go out and have a bunch of coolant in drive under where reservoir is which made me think it was burping through there and overflowing but cannot find any evidence of it.

So...sorry for long winded initial post but after several days burping and reburping, topping off, checking for leaks and watching coolant level I cannot seem to get to the bottom of an overnight burb or leak that I can never find while running or watching it. Just a mysterious overnight burb of about a quart of coolant.

 

[OSS]

Losing a quart of coolant every night with no signs of drips = bad. Really bad. The engine shouldn’t lose any coolant for months.

 

[3_puppies]

losing a quart a night?
have you not topped it off and see what happens, does it lose another quart or does it level off?

 

[TexasLandCruiser]

You cycle your heater in the middle of all this?

 

[ColnagoNH]

Yes I have burped multiple times always with heater on high and keeping leveled off. It seems to do it if I drive for more than an hour at a time. Have not noticed on short drives as think I have it solved and then will go for a longer drive and check it a few times as it cools down and no issue. Then walk out the next morning and it will have leaked on drive again. It really does seem like there is some kind of an air lock that I have not addressed that takes time to release or something. Almost like the engine cools off completely and then for some reason it burps or maybe a crack somewhere opens enough to leak always in same spot under front drivers side.

 

[Gimme a 60]

Check the dipstick for coolant.

It’s all I know.

 

[ColnagoNH]

None on dip stick and I just dropped oil pan a couple weekends ago and nothing in pan either.

Think I have it figured out as saw on other threads the Champion radiators, which previous owner installed, will leak at seams and looks like that is what is going on. Not sure why it has been leaking randomly but may just be a top seam as I topped it off this afternoon doing more investigation and it started leaking while I could watch it and seems to be coming from a seam as slowly drips around one. Will work to repair and confirm.

Looks like I need to start working on a Mosley radiator.

Sorry for rookie issue as should have been able to find it was a leak on my own just could not figure out why I was only seeing it overnight.

 

[Spook50]

With no signs on the ground of major leakage, I'd say check the underside of the oil filler cap for any milky residue. I've found that on other cars where they were losing coolant and I didn't see any sign on the dipstick.

If in fact you are losing coolant from the top tank seam on your radiator, you'll notice (assuming you have Toyota red coolant) a lot of pink buildup all over in your engine bay. This is exactly what happened to me a few years back.

 

[ff347]

I had an issue like this with a champion, it would heat up and seal up! I am on my last champion as I will consider something else when this one eventually goes. The shipping is crazy expensive for the free replacement and I would be close to having purchased a custom by now. Just my experience.
I would try some kind of metal epoxy to once you find the leak if it is the radiator.