Coolant Question

[m75]

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Ran at idle today for about 30 minutes. Temp gauge showed normal. After shutoff and waiting one hour, I opened the radiator cap and found this green stuff, generally the antifreeze color but "stuff" floating throughout. Ideas?

[rickf]

The "stuff" looks like oil. Which generally means a blown head gasket. But if you did not have any excess pressure or temp problems it may just mean someone previously had a blown head gasket and this is past residue. You can get a test kit to see if there is combustion gas in the radiator while it is running. Here is a link to my search for those kits. many flavors and prices. You do not need a top of the line kit for one job. Or you could take it to a garage and have them test it but that would probably cost you more than the most expensive kit here.

https://www.google.com/search?q=head+ga ... e&ie=UTF-8

Get some of the gunk on your finger and see if it feels like oil or if it maybe feels like Bars Leaks. Possible the radiator was leaking at some point and Bars Leaks was added.

[steveo]

great advise from Rick as usual.

When you drain the radiator you might consider flushing it and might want to make sure ya drain and flush the block too.

I had a head gasket leak on an oil port that went into the
Piston bore and not in the radiator coolant. Was bubblin on the passengers rear where the head meets the block at piston 3
Pulled the head and from the clean-up and everythin else I drained the radiator and then the block. When I drained the block I had a good amount of “junk”come out, and not just from the amount of cleanup I did on the head/block surface.
I also flushed the block while I had the head off.
(Oil change too).
Just in case if you’re not aware, I think all the m151 engines have this but theirs a drain on the drivers side rear of the block below the exhaust manifold. Kinda tucked back in there and a little hard to see if you don’t have the manifold off or where it meets the exhaust pipe at the flange.

Hope it’s a nothin for ya.
Have a blessed day.

Steveo
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[rickf]

Jim, When I looked at that last night I only had one eye open. I just zoomed in and zoomed again and that stuff looks like flakes. I will bet that is some sort of stop leak. As Stevo said I would do a complete flush and maybe just fill it with straight water the first time you fill it up and run it up to temp with the cap on to see if you have any leaks. Something you can try is to drape a tarp, blanket or similar in front of the radiator to stop all air flow through the radiator and then monitor your temp gauge. Let it get up to close to 200 degrees and shut it off and watch for leaks. After about ten minutes you can remove the cover on the radiator and start it back up, it will cool down quite quickly. Once down to normal temp shut it down and let it sit for a while until you can remove the radiator cap without becoming lobster dinner. See if you still have the stuff in there. Yes or no what I would do while I had expendable water in there is fill it right to the top as far as it will go and then start it up with the cap off. Watch for bubbles. If you see a couple that is no big deal but if you see a steady stream that does not stop the whole time you are running then you have a blown head gasket. If it turns out you do then I will bet money it is on the passenger rear side of the engine. The head bolt holes on a lot of these engines were not tapped fully and the bolts bind before they hit the proper torque. The torque wrench say it is there but it is only binding on unfinished threads. This is a simple fix, just get the proper size tap and run to the bottom of the whole. Make sure you get a bottoming tap. I run a tap thr9ugh every hole on every engine I build, no mater the size or brand. I want to know those holes are clear. Them blow them out with air. Have the top of the engine covered so the stuff from the air blast does not end up inside the engine.

[m75]

Thanks Rick and Steve. Moving furniture today but when that dust settles, I'll look into the recommendations, whether they're based on just one eye open, or both!