Head Gasket, Water Pump + Engine Mounts
 

So my misfire has finally been diagnosed to a bad head gasket and engine mounts. (yes both combined has caused the horrendous idle that has plagued me for quite some time).

I guess it took 5 different mechanics to finally tell me what the damn problem was :mad:

Well anyway....He said the current problems with the car are that the water pump is leaking, head gasket is causing compression loss on leakdown test and the mounts are shot.
I can't afford $1500 to pay for the head gasket which I was quoted...

1) Water Pump -- Should I stick with OEM for the pump?

2) Head Gasket --
---a) Is this DIY'able?
---b) Any special tools required?
---c) Should the head need reconditioning at 87k miles??
---d) How can I tell if the timing chain is okay? I would assume its fine at 87k miles.

On that 1988 model I would have the head re-done. Valve guides wear quickly.
There are several special tools that you need. Including the special splined socket for the head bolts.

Other than the OE pump...I would consider a NEW Graf pump.

You can DIY that, but you will need a good manual. Figure two days (a weekend) of work for disassembly and reassembly. I rented an engine hoist since I worked alone and left the intake manifold attached.
Would I do it myself again? No, just because of the time involved.

Also, I would really, really convince myself that the headgasket had blown. If it's bad enough to cause low-compression misfires, I would think you've got other symptoms as well (exhaust & oil in coolant, coolant on plug, oil leaking out). 87K does sound low, but the age may have played a role too.

Thanks. Yes I will go new for a water pump without doubt. So which would you say is the best, OE or Graf?

Yeh my dad has an engine hoist. I have done valve stem seals

---

What about the timing chain? At my miles, should I "need" to replace it or would you recommend just leaving it/doing the guides

Not to refute or ignore the advice of experts, but although the items you described would probably need replacing considering the age and mileage on your vehicle, NONE of those issues contribute to misfiring!!!

In fact, your car would still run and drive normally, although the oil leaks and overheating issues would be a problem.

1. Is your car overheating, and are you seeing oil in the coolant reservoir or prolific oil leaks around the head? If you can say NO to all of these, I'm not sure why that diagnosis was made?

2. MB water pumps tend to fail dramatically...one day all is well, the next, a Valdez-sized coolant spill resides underneath the car! If this hasn't occurred, then you don't have a water pump problem either.

3. Collapsed or worn engine mounts would contribute to vibration..usually noticeable at idle but sometimes misinterpreted as suspension vibration at highway speeds.

Although I have a different engine than yours, I had the above items replaced at one time or another, and none of them were replaced under the guise of a misfiring issue. The $1500 quote for the gasket is pretty decent, but add the cost of the other items, and that's a big chunk of change for reconditioning your engine compartment, only to have the misfire problem not get solved.

My two cents...for whatever its worth.


P.S...has your engine harness ever been replaced?

Headjob and waterpump
 

Ps2cho
The tools you will need should be aquired aheas of time(I think you can get them through this site),Allow 3 or 4 days for this project since after the head is off you will send it out for possilble resurface and deffinate valve guides and reface valves and seats.
While the head is at the machine shop clean up the block lightly oil the exposed parts of the cylinders and replace the waterpump (a factory reman. waterpump cost same as new aftermarket and just as good) Don't forget new bypass hose ,serp. belt and check the tensioner before you reassemble.
Mike

ok great.

I just got the car back and while at the shop he said later that night he probed the oil pump and the receipt says "Transmission oil pump and rear main seal both leaking".....Is that something that needs to be done right away can it wait?

Off subject but that's a nice looking car.

Thank you :)

I am thinking that I may leave the head gasket for now and just do the water pump + engine mounts.

This there any faults in doing this? I mean obviously the misfire wouldn't be fixed, but its a huge job and I already have other things to do....so could the head gasket wait lets say 6 months til I have the rest of the problems resolved, or could it cause other damages? As far as I know, the worst that is happening is coolant leaking into the cylinders....

Is any coolant going missing, any overheating, or coolant/oil mixing? The gasket could be blown between cylinders, causing a misfire, but I don't really hear of that happening very often, especially on naturally aspirated engines.

Yes coolant does slowly go down and I gotta top it off every 3-4 months....

If a gasket is blown between cylinders, is that something maybe I should do for good measure when I go in to do the head gasket? Or does it require alot more work? I've never taken off the head before so I don't know.

But the coolant could also be going down just because of the bad wapu (wasserpumpe). Recommend replacing wapu first and continuing to diagnose the headgasket/misfiring.
You never said whether your spark plugs indicated anything on the suspect cylinder.

Its a random sputtering really....my mechanic said he was 100% sure that the head gasket was causing the misfire...

I think I am going to leave the head gasket until I have fixed the water pump + engine mounts.

Hate to say this, but considering all of the parts that get disconnected to do a head gasket, the water pump replacement is FAR easier while the head is off...might as well do a full circle rebuild...worth it IMHO.

Look at all that room! BTW, the intake manifold was removed because it had a crack...the source of my hesitation and bogging at speed.

http://i11.photobucket.com/albums/a1...r/IMG_0325.jpg



Plus, your mechanic should be able to clean the pistons and cylinder areas:

http://i11.photobucket.com/albums/a1...r/IMG_0147.jpg


And send off the head for reconditioning...

http://i11.photobucket.com/albums/a1...r/IMG_0150.jpg

http://i11.photobucket.com/albums/a1...r/IMG_0154.jpg

Great pictures thanks. I can see what you mean. How many hours would you say it would take to get to the gasket exposed?