After unsuccessfully resolving an external coolant leak from under the no. 6 exhaust manifold port, I am realizing that I probably have to bite the bullet and replace the head gasket on our 1997 960. The car runs fine and to my knowledge has never overheated. The leak will empty the coolant reservoir in 1000 to 1200 miles.

While I can handle the wrenching aspects of the head gasket job, I know nothing of cylinder head reconditioning or machine work. I was hoping someone could educate me or offer some tips on what to look for and ask for from an automotive machine shop. Is it absolutely necessary to have the head reconditioned or machined? What service should I ask for?

Thanks in advance!

I've obtained a rebuilt head, a few of the Volvo special tools, and am preparing to dive in this weekend. Will let you know what I find.

My current symptoms are as follows. 242k, 1997 960 -- car had a small coolant leak for some time at the left rear corner of engine block. The leak drips down the bell housing onto the exhaust header. It is NOT from the heater hoses or fittings. About a month ago, the leak became larger to the point where it would empty the coolant reservoir in 400 miles.

Since the car was running fine, and there was no evidence of oil in coolant or or coolant in oil, I dismissed it as a corroded water pipe or weeping heater hose connection. After replacing all the hoses and treating the pipe for corrosion did not resolve issue, closer inspection revealed the leak appeared to be at the corner and below the no. 6 exhaust manifold runner originating from head gasket seal. I added K-seal leak stop as an interim protective measure (wife's daily driver) until I could obtain the head, parts, and time to do the job. It slowed but did not stop the leak.

I've read about other 960s with similar symptoms, most of these have been head gasket leaks.

An additional symptom is that pressure in the coolant reservoir remains quite high even after engine has cooled.

I don't know if the head has been off this car before, but I guess we're going to find out!

While checking is a good ides, you should first remove the head and see why the gasket blew.

On a high mileage chevy V-8 that I had I found that the bolts at the ends of each head were only finger tight!

On out '95 854 with 96K, some of the gasket had corroded away and was nowhere to be found! I'll see if I can find the pictures.

I had great luck with Rick Gorka who owns a Machine Shop in Clifton Park. He skim cut the heads on all 3 of my 93 240's. two of the three had developed an external coolant leak. Each time I believe he milled 6/1000 and the cars ran fine and didn't leak afterwards.

He owns his own shop and is quite meticulous.

Down to one 240 :(

Marty




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Adirondack Blues, I'm assuming you are somewhere near the ADK in NY state...

FYI: I have used Quality Foreign Car Care in Ballston Spa (near Saratoga Springs) to wrench my Volvos for years. One of the only places I let touch my bricks. I will drive the 3-1/2 hours up from Brooklyn for them to do work I can't or don't want to do.

Give Paul a call and see if he can recommend a machinist or head/motor source around the ADK.

http://www.qfcc.com/

Route 50 & Saratoga Avenue
Ballston Spa, NY 12020
Phone: (518) 885-1781

On the 5-cylinder I just did I had the tank it, check for flat, and pull the valve stem seals (I had pulled the valves). The stem seals need replaced, the head needs to be flat and it needs to retain the factory mill pattern or if shaved have a similar level of not-smooth, it is good to have valve seats touched up (not enough materials to grind them) and IT MUST be CLEAN and stay that way. Have them run spark plug tap on the holes to make sure they are still viable.

It does not have a valve cover gasket. It uses microns thick coating of anaerobic sealant put on with a roller before you three-stage tighten 50+ bolts on the cam cover.

Oh, and get and angle torque gauge (about $15 on Amazon) and be prepared to scare the crap out of yourself with the REALLLLLLLY long final angle torque on those head bolts.

This car has 240k miles on what I assume is the original head gasket. We've owned it since 200k. I don't know if the valves have ever been done in the past, but I would assume not.

Cleaning the head I can probably handle.

Would I be stupid to replace my own valve seals and lap the valves? After some internet research, it looks like only a few specialized tools are required. Also, re cleaning the valve seats I have seen it done on a brass wire wheel on a bench grinder. Is lapping the valves always required? Looks time consuming but certainly doable by hand.

If, and I realize that could be a big if, the head is NOT warped, can the surface be roughened by gentle sanding on a flat surface?

Researching machine shops in the area, but then again I'm usually too stupid, cheap, and stubborn to pay someone else to do something I can do myself.

Thanks

I am not one to tell people to leave things to the professionals but if you want to mess with this "precision" an engine that has +200K miles be sure you are prepared to the human and financial costs if you fail.

The valve guide seals are easy if you buy the right tool for extracting them which also means buy the right valve spring compressor (these are not for rent at Autozone). By easy I mean very possible but time consuming and annoying (I did a 5 cylinder and wanted to kill the engineer after).

Lapping the valves is not required but good practice.

Running a tap down the spark plug holes is absolutely something you can do.

Checking the head for flat is something can do but please make sure you understand the implications of not using the "correct" tools for the job. In short, you have to do about 4x (diagonally each direction, left long, right long, center long, left short, right short) as many checks with you machinist straight edge and a feeler gauge as you think you need to.

Now, if it is flat DO NOT MESS with the factory surface. Make sure it is perfectly clean with no residue of any sort of gasket material. Same for the cam cover and the block surface.

Once you have done all that, make sure you run a chasing tap into all the head bolt holes until they come out clean. If I am not misremembering, you are putting 135 degrees of torque on those bolts after the 68 lbft mark.

My current thinking is to buy a rebuilt head. This will save time and also the trouble of the reconditioning. Any thoughts?

I would be more inclined to buy a used motor with a warranty, replace the T-belt, water pump and seals...

If you find someone that sells these heads rebuilt, make sure you get details on what a rebuild entails. You still have to clean the deck, chase the bolt holes, install, time and install the cam cover.

Is the issue downtime, lack of trusted machine shop or ?

I completely understand any of those.

A head does not always have to be rebuilt for a head gasket swap.

Valve clatter? Guides going? Are the valves holding clearance?
How many miles on the motor/head?

I'm not a 960 expert... Hopefully 960 will give specific advice

Do you have a shop in mind for the head work?
Finding a good shop is an important step.

I think the most important thing is to test if the head is warped and can even be reconditioned. Tested with a known straight edge along the face. A warped head will put uneven pressure on the cam bearings and equals a dead head.

Then what damage was done to the head surface by the hot leaking coolant, and can that be removed by skimming the head surface??

After that...
Will you regrind the valve seats? Three position grind (better flow)?
New valve guides? New spring retainers?
How are the spark plug thread holes?

Services would be...
Dipped or tanked to clean the head.
Skim or deck the head surface to make it flat again.
Recut the valve seats.
Disassemble/assemble with whatever new parts are needed.

And I'm sure I'm missing something...

Good luck.

hi sages - this thread illustrates the 3 classic questions a backyard wrencher must answer when contemplating sending something out for repair. to wit- is the mechanic competent to do this repair; is the mechanic honest; is his pricing reasonable. not hard to find 2 of these 3 requirements but all 3 in 1 mechanic is tough. have found a good shortcut to finding this out is internet inquiries. after all none of us want to go to the cleaners? whose been there? thanks tons oldduke