1987 6.2L Weeping Coolant Between Head and Block Front Left Corner, how to fix?

[Bulldogger]

I mentioned this in my HMMWV rebuild thread but don't think anyone noticed, so putting it out here.

I've noticed what appears to be a new tiny bit of weeping between the head and block at the front left corner of the motor. Tiny, tiny bubbles when it's running. I don't think it's using up much coolant, my loose hose clamps were the culprits there, but it's not supposed to happen, so I want to try to fix it if possible.

I know there are block seal products, but I have always had bad luck putting that stuff into older vehicles. These products seem to only accelerate the death of heater cores and radiators.

I haven't tried to check the torque on the head bolt there, or the others, but she is pretty old and I have found that many clamps and bolts are loosened due to time and heat cycles. The valve cover bolts were very loose. (I know they're not supposed to be "farmer tight", but these were weeping oil and a few cranks seemed to help.)

I welcome advice and "been there" experience.

A poor quality video (you're welcome!) is at the link below. At about the 13s point you can see the teensy bubbles and the wetness on the block is obvious. This is not ATF from my steering pump replacement, I'm sure.

Thanks for the help.

Bulldogger

http://s383.photobucket.com/user/Ti...7-47FA-B290-84218103E237_zpsi8dwk5vu.mp4.html

 

[79f250guy]

To do it the right way probably goin to have to pull the head and replace the head gasket and get a heads checked to hope it's not cracked.

 

[79f250guy]

To do it the right way probably goin to have to pull the head and replace the head gasket and get a heads checked to hope it's not cracked. Maybe start by getting a coolant pressure tester and see how bad it is leaking
down

 

[gcbennet]

I'd say that if the head gasket is compromised in one spot due to age, etc other failures probably aren't far behind. But, if you're going to do one, you might as well do them both. I recently had the same issue and decided to pull the heads once I started blowing white smoke on start-up from coolant leaking into one or more of the cylinders. I also used the opportunity to thoroughly clean and inspect everything, repainted components, replaced older lines, hoses, etc. and put everything back IAW the TM's that prior owners had either removed or jerry-rigged.

 

[Bulldogger]

Thank you for the replies gentleman. I don't have the luxury of good working conditions to remove and replace heads now that the cold-weather has arrived.

Are there no effective temporary fixes, or can I just leave it to weep?

Bulldogger

 

[dilvoy]

Don't forget that GM used torque to yield bolts for the head bolts. They are probably cheaper! Jerks! They are a one time use bolt so buy new ones if you pull the heads. If it is tiny leak, then just watch the coolant level until spring time then maybe fix it.

 

[Bulldogger]

dilvoy, interesting about the bolts. I'd never heard of such a thing. I have seen head bolts get annealed, slightly, from heat and lose their ability to hold a good torque, but that was on an old Harley.

Is there a risk tightening the GM bolts in place? I realize it's unlikely to stop the leak, as once a gasket starts letting stuff by the horse is out of the barn.


Bulldogger

 

[gcbennet]

I suppose you can try re-torqueing the bolts as a bandaid measure and see if that will at least buy you some time. The TM is very specific about the process so make sure you follow it to the letter. You'll also need an 18mm socket for the job, which I had to go out and buy because none of my sets come with that size. lol I've heard of certain head bolts stretching on installation and needing to be replaced after removal. However, I personally don't recall the TM referring to the 6.2 head bolts as a discard item. In the best interest of keeping costs down I merely cleaned them up and gave them a thorough inspection prior to reinstallation. Mind you, I'm not a career auto mechanic so if reusing head bolts is a faux pas in the industry it looks like i'll be pulling and replacing.:-s

 

[infidel got me]

Bulldogger-- if it were me, I'd leave it alone. I know its tempting, but you may make a slight leak worse. I do have MR.MURPHY'S cell phone # if you want to give him a call and see what he thinks. lol

 

[Bulldogger]

Good point. We'll see. I'll watch it for a while and try to get a feel for how bad it is. Might have always been there since I woke her up from her slumber.

BDGR

Bulldogger-- if it were me, I'd leave it alone. I know its tempting, but you may make a slight leak worse. I do have MR.MURPHY'S cell phone # if you want to give him a call and see what he thinks. lol

 

[gcbennet]

Dilvoy- thanks for the info about the head bolts. In spite of what the TM says, or better yet doesn't say, the head bolts are certainly a discard item. I corroborated this fact with a friend who's owned a local garage for the last 30+ years- once I told him the torque values (20, 50, then another 90 deg turn) he knew right away they were the stretch kind. Two sets of new bolts cost me over $100 at my local Car Quest, but at least they come with the pipe sealant on the threads and heads right out of the box.

 

[Retiredwarhorses]

They are called TTY " torque to yield" they are a one time use item. I always suggest you go to head studs and get away from bolts....

 

[Bulldogger]

Thanks for the details gents. Looks like I will keep an eye on it and steel myself to replacing the head gaskets in the Spring (if she makes it that long!).

Bulldogger