PurplePeopleEater

Hi all.


Introduction:
I am a long time reader, first time poster. About 5 years ago, I bought a 82 928 European spec. It was repainted "plum" by the PO. I changed the rims and tires, and recovered the interior with new leather, and upgraded the door panels with those from a later model.



The car had about 99k km on it (~60k miles), and I replaced almost every hose or belt I could find.

I've never had any serious issues with the car, until now.



Problem:
I was close to home, and noticed the coolant light come on. When I got home, I saw a leak coming from the rear of engine on the drivers side. At first I thought it was a heater hose, or something easy (I have had hoses go bad on the car before).

After some looking, I found that the leak is coming from here:


(picture taken with an old scooter mirror)

I've looked all over the forum (as usual), but can't find what this is, or how to fix it. Please tell me its not a head gasket leak. The Shop manual DVD says that I have to remove the engine to remove the head. What a pain.

Any ideas?

Thanks in advance.

Greg

Lizard928

Its not a head gasket problem.

Does that make you feel better?

Lizard928

It is actually not a headgasket. But instead it is a frost plug.

Judging from the location though, it is at the back of the engine. You MAY be able to remove the front one (matching front/rear) and use a rod to push that out. Then get fancy to insert the new one.
You may have to pull the timing belt etc apart to do this though.

The other option which I dont recommend is Barrs stop leak or the like.
I dont recommend it as a number of cars that I have seen it in have had plugged radiators and other deposits....

Dave928S

Here are a few pics of what you're dealing with. Over here it's called a welch plug ... and I agree with Colin, that's what appears to be leaking.

Looking at my 16V heads though .. unfortunately you can't push a plug out from inside from the other end ... there's too much chamber and port casting in the way ... you just can't get a straight shot.

I hate to say it but I think it's going to be really difficult ... or maybe impossible to do it with the head/motor in the car. I've pulled my 16V and had it stripped down in 8 hours so it's not such a huge job. You could spend way longer than that stuffing around trying to fix this one issue in the car. If you pull the motor you get easy access to check/fix all the other PITA in car issues.

I also agree with Colin on barrs leaks ....don't ...

PurplePeopleEater

Firstly, thank you very very much. This forum has been a lifesaver many times over. You guys are really great.

Well, I'm happy that its not a head gasket............I think.

I used Barrs one time before (a few years ago), and I had to change the radiator a little while later anyway. It was a mess. I will never do that again.

There is the block plate on the back of the head near the plug. Could I access it from there?

If it does come down to pulling the engine, do any of you guys have a parts list that I can work off of (gaskets, etc.). It takes about 2 weeks to get parts here, so I would like to be well prepared before I attempt this job at my local DIY garage/auto craft shop.

Thanks again.

Manfred

Where are you located?

Lizard928

Sorry, been awhile since I have had to look at that on a 16V.

Definitely castings in the way.

It may be possible to tip one end in and extract it that way. But I would not recommend it.

I suggest pulling the motor, or at a minimum disconnecting and sliding everything forward.

daveo90s4

I can't quite make out how much room you've got to work on the job with the engine still in. But if you did have some working space I think I'd be inclined to have a bit of an initial play to see if it could be done without taking the engine out. I'd try to use a dremel to cut a groove part way through - but not right through - the frost plug. Then I'd clear away all the filings and use a sharp screwdriver to drive through the weakened frost plug (ie no metal filings / shards in the water jacket). Then I'd try to gently pry the frost pug out, working it a bit on each side. If that worked then you'd be able to replace this frost plug. But if I wasn't making good progress with this approach in a short time - a couple of hours say - I'd resort to pulling the engine. You wouldn't necessarily need any gaskets (except maybe for exhaust flange gaskets) because you would not need to remove the heads or do any engine stripping to replace this frost plug.

Good luck (where are you - looks a bit like Italy maybe?)

the flyin' scotsman

If the issue is indeed the pictured 'frost' plug you could remove attempting the self tapping screw method.

Get a short and fat self threading screw, screw into the plug to about half its thread length then dependening on room use the most suitable tool to pull on the screw head and pop out the plug.

Once its out we can discuss fitting the new plug......good luck

Randy V

What would be the harm in just pushing the leaking plug into the engine case and installing a new one?

It appears to be captive in that space and seems that it wouldn't create a coolant flow impedence.

Just a thought.

Lizard928

Randy: Our master of hacks.....

Randy V

Why not?

Speak up, exhalted one.

Lizard928

Well, if you really wanted to hack it, you could just dry it all off, rough it ups slightly and then just JB Weld over it too.......

Imo000

Better yet, get a can of Block Seal, follow the instructions, don't skip any steps, and you'll be good to go.

DR

Be sure to check out the rest of the motor carefully, every 928 Head I have seen with a busted and/or leaking freeze plug had worse damage inside.

Last one I saw was Don Hanson's Mega Dollar Race engine...needed new head freeze plugs installed...along with new or repaired heads?? and another block, very sad :-(

Not trying to make you panic, just would rather check it out well if it were mine, before taking it out and driving the heck out of it, or continue doing so.

You can also buy an easy and inexpensive Head gasket leak tester for around $50 (multi use) that will tell you in just seconds if you have combustion gases in your coolant.

It is used and approved by Major Auto Manufacturers....for gas and diesel engines. UVIEW 560000 Combustion Leak Tester