Radiator Boiling Over (2 Viewers)

[AYM707]

1983 FJ45 - stock

After a 45 / 60 min drive normal highway; my radiator fluid is boiling / overflowing from reserve tank release.

I am running a mix of anti-freeze + water and there's no thermostat. My temperature sender was dead. I had previously flushed & cleaned the system several times before and the system was empty for a long time. I feared a head gasket leak as the coolant colour changed to an dirty olive. Also at start-up, there are a "few" drops of fluid coming out of the exhaust. But that stops after a while; but no smoke.

I have jacked the front help release the bubbles, there was plenty. But was convinced, it was a head gasket leak - maybe a minor / small leak. Ordered some head gasket sealer (K-Seal & Blue Devil) and a tester. Tested it, and the fluid remained blue; but there were a constant stream of bubbles coming out. Ran it for about an hour (mostly at idle), the fluid never changed colours, but the bubbles did not stop.

Does this mean I have a very small leak or should I be looking at some place else? The water pump is functioning; when you squeeze the radiator pipe, you can feel fluid flowing. I have replaced the temperature sender and will take it for another test drive.

Debating if I need to use the head gasket sealer? Appreciate your input.

 

[charliemeyer007]

Maybe your test solution is bad - bubble some exhaust threw it to see it changes color.

Cold with the radiator full to the cap, will push a fair amount of coolant as it heats up. If cap and overflow tank are working correctly it will pull the fluid back in when it cools back down.

I always go to a steep incline to get the radiator cap well above the heater so it will burp properly with the cap off and engine running. I clamp off each heater line (front and rear heaters) briefly to force the flow threw the other one. Heater valve would be screwed out to wide open.

Start up condensation is normal.

 

[Green Bean]

These doodads work remarkably well and they come in quite handy.

Amazon.com

 

[brian]

Hg or a cracked head

 

[Steamer]

there's no thermostat.

Probably not your issue but worth mentioning.
Unless you have a bad thermostat, running without one won’t improve cooling. The T-stat on our 40s don’t just open and close. There’s a bypass involved.
When the T-stat is closed, the bypass is open. (Some water bypasses radiator)
When the T-stat is open, the bypass is closed. (All water goes through radiator)
With the T-stat removed, bypass is always open. (Some water can bypass the radiator)

 

[DeskJock]

These doodads work remarkably well and they come in quite handy.

Amazon.com

This is rad. thanks for the tip.

 

[TheBussman]

I've seen the block test fluid not work before, need a have a good tester that defuse into very small bubbles to work. I have a 2 stage tester and it's almost always the 2nd stage that can find the leak not the first. cracked head or head-gasket. Recommend fixing it instead of trying to use sealer, headgaskets don't get much easier then a 2F.

 

[samatulich]

I'd try burping the system again. Using a "spill proof funnel". I would also loosen the temp sending unit that is located on the cylinder head, do this while it's running. Just need it to be cracked open, you're letting any air escape.
Trapped air can cause things to heat up.
I also massage the upper radiator hose. Squeezing it ever so gently to help burp the line.
Lots of tricks to getting ALL the air out of the cooling system. Just elevating the front doesn't necessarily work.

 

[Pighead]

A compression test might be helpful

 

[AYM707]

Maybe your test solution is bad - bubble some exhaust threw it to see it changes color.

Cold with the radiator full to the cap, will push a fair amount of coolant as it heats up. If cap and overflow tank are working correctly it will pull the fluid back in when it cools back down.

I always go to a steep incline to get the radiator cap well above the heater so it will burp properly with the cap off and engine running. I clamp off each heater line (front and rear heaters) briefly to force the flow threw the other one. Heater valve would be screwed out to wide open.

Start up condensation is normal.

I am using the Reld test kit. I checked the fluid against the exhaust, it turned yellow immediately. So I don't have a head gasket problem? This is nothing but a big air bubble issue??

Thought I would check the thermostat, ended with 2 broken bolts and the housing appears to "stuck". Can't pry it open. The 2 bolts that did come out were badly rusted. I sprayed penetrating oil on the bolts holding the housing to the engine block. One is slowing beginning to turn, but I'm afraid to apply too much force...don't want to end up another 2 broken bolts on the engine block.

 

[Steamer]

Yup, the dissimilar metal corrosion at the T-star housing is a problem and snapping or stripping bolts isn’t un-common. Sometimes the housing gets ruined also. I’ve purchased new & used T-stat housings from vendors here on Mud.

Even though you have flushed the cooling system several times, it doesn’t necessarily mean it’s clean in there. It’s very possible to have crap coating the walls of the cooling jacket that ordinary flushes just don’t remove. And then with the garden hose running into the radiator with the block and radiator draining crystal clear water, it can give you a false confidence that it’s clean in there.

Gotta ask, your block drain flows freely right?

 

[AYM707]

Yup, the dissimilar metal corrosion at the T-star housing is a problem and snapping or stripping bolts isn’t un-common. Sometimes the housing gets ruined also. I’ve purchased new & used T-stat housings from vendors here on Mud.

Even though you have flushed the cooling system several times, it doesn’t necessarily mean it’s clean in there. It’s very possible to have crap coating the walls of the cooling jacket that ordinary flushes just don’t remove. And then with the garden hose running into the radiator with the block and radiator draining crystal clear water, it can give you a false confidence that it’s clean in there.

Gotta ask, your block drain flows freely right?

Block drain? Can you send me a picture of where it should be?

I replaced the temperature sender and noticed there was green coolant in that location.

 

[DeskJock]

Yup, the dissimilar metal corrosion at the T-star housing is a problem and snapping or stripping bolts isn’t un-common. Sometimes the housing gets ruined also. I’ve purchased new & used T-stat housings from vendors here on Mud.

Even though you have flushed the cooling system several times, it doesn’t necessarily mean it’s clean in there. It’s very possible to have crap coating the walls of the cooling jacket that ordinary flushes just don’t remove. And then with the garden hose running into the radiator with the block and radiator draining crystal clear water, it can give you a false confidence that it’s clean in there.

Gotta ask, your block drain flows freely right?

Grrgh. Sorry brother. Mix in so heat with the penetrating oil. Heat/ cool / oil - a few times.

I’ve started using Kroil as a penetrating oil, and not only does it smell good - I believe it works the best of the oils that are available.

 

[3_puppies]

Block drain? Can you send me a picture of where it should be?

I replaced the temperature sender and noticed there was green coolant in that location.

block drain will be exhaust side of block, close to the firewall, cylinder 6 area between oil pan and head.
if it hasn't been opened you may need to use a stiff wire to poke inside and clean to get flow thru the opening

 

[Steamer]

The block drain is the lowest point in the cooling jacket where crud likes to settle & build up. If opening the valve doesn’t let it flow than you’ll need to unscrew the whole valve. Clearing it out can vary anywhere from flushing or poking it to even in extreme cases (like mine), a drift pin and hammer to break through hard solidified aluminum powder leak stop that the previous owners had dumped in there.

 

[3_puppies]

pics of block drain

 

[Pighead]

More pics of block drain

 

[Skreddy]

Are you filling the radiator and overflow bottle all the way? As mentioned, this can cause it to push out the radiator and into the overflow bottle which, if already full, will spill out. Needs to be a little room in the radiator for expansion.
Do you have an infrared temp gun you could check temps with when it’s boiling over? Without knowing actual temps there’s no way to know there’s an actual problem.

 

[DeskJock]

More pics of block drain

View attachment 3688993

View attachment 3688996

View attachment 3689003

Nice job not only getting them out, but also there reusable! Thats a double win!

 

[AYM707]

I still haven't removed the engine plug. I was a bit afraid of breaking the bolt, even though I put alot of penetrating oil. I have chasing the temperature / boiling situation. Installed a new temperature sender, and that is working now. Made my own bubble extractor I can do this with the engine hot. Rev'ed the engine and ran it for a good 30 min and there were alot of bubbles coming out. I repeated the process...allowing the engine to cool before rev'ing it up again. When it finally cooled, it did suck most of the coolant into the system. I think I will repeat the process a few more times..