Head Gasket Replacement

[brettj]

Just a follow up on my headgasket situation. I had another mechanic take a look at my car. He said that the headgaskets usually leak at the rear corners of the motor. He felt that my headgaskets are not leaking. What we did find is that my left bank brand new valve cover is already leaking badly. I can't believe it! I just installed new covers and valve cover gaskets last month! That left bank cover was leaking with the old covers installed and I thought I solved the problem with the new ones. What could be the problem here?

The new mechanic also told me that a headgasket job would cost me $4,500. He felt that if you change the head gaskets you should also do a valve job and change the timing change guides as well which makes sense. He also felt that with only 163,000 miles on my car that I could get another 100,000 miles out of it before needing headgaskets etc. I'm going to make an appointment with him next week to see if we can solve the leak issue once and for all.

[oscar]

That's good news.  Time to have a closer look at that cam cover.   IMO persistent leaks from the these cam cover gaskets can occur due poorly fitted gaskets, warped cam covers or damage to the mating surfaces on the head's.  For damage, it could just be a screw driver mark or gouge that causes a seep in which case a sealant might be used when putting the covers on. (no recomendations there from me, haven't used any) or remachining which is too big a job so I'd go sealant if that was the case.   

The cam cover could have a crack in it too I suppose, though it should be seen during a thorough inspection and if it's warped you should be able to get a good 2nd hand one. 

Back to the gaskets themselves, if your 450 is like my 350 in regards to fuel supply and return line location then the left cover is a bit of a PITA to take off and put on.  The fuel lines make an inverted "u" shape where they cross over the cam cover to make room so you can lift the cam cover over the aft cam bearing towers.  I've always had to wrestle mine a bit and find the cam gasket will often fall off the cover during removal and assembly of that left cam cover.  It's too easy for the gasket to be pinched when trying to keep it all together and it's highly likely that your gasket has been squashed and isn't fitting properly near cylinder 8. 

Last thing, seepage can occur from not having the copper washers on the covers' retaining bolts.  Good luck, it's sounding promising.

[brettj]

More bad news.... I took the 450SE to another mechanic to get a second opinion on the headgasket leak issue and the other issues with the car. I was informed today that the headgasket is definitely leaking. I was quoted $4.500.00 for head gasket replacement.  Very disappointing.  Since I've spent over $40,000 in repairs, another $5,000 is breaking the bank. I've decided to put the car up for sale.

Having put so much into the car and that it needs more work, I'm not sure how I should price it. Has anyone out there ever sold a W116? How did you decide on an asking price?

Thanks,

Brett

[koan]

More bad news.... I took the 450SE to another mechanic to get a second opinion on the headgasket leak issue and the other issues with the car. I was informed today that the headgasket is definitely leaking. I was quoted $4.500.00 for head gasket replacement.  Very disappointing.  Since I've spent over $40,000 in repairs, another $5,000 is breaking the bank. I've decided to put the car up for sale.

That's disappointing to hear.

No idea what you would ask but you'll only recover part of the money you invested in it. The fact that it requires $5k to fix reduces the return even further.

I wouldn't be selling the car I'd keep and spend the money required to fix it, even if I had wait 12 months.

That's just my view, other folks may think differently.

koan

[s class]

I imagine a lot of that bill is a labour charge - and it is a very high charge - what would fair hourly labour rates in your area be?  Did they give you an indication of exactly what the scope of work will be for that price?

You really could do this job at home yourself - if you lack confidence, maybe you have a friend who's opened engines before that could help?

I agree with koan.  Don't sell the car, calm down and look at a long term picture here.  In the grand scheme of things, a leaking head gasket is a nuisance problem, not a serious terminal illness.  If it takes a year before its sorted, so what?

[brettj]

I  agree with  both of you in that I should hang on to the car but it is  costing so much money to repair or I should say rebuild  and the problems never seem to end.   I could have bought a brand new MB E class with the $40,000 I spent on the 450. Then again, the new MB's are nice but they don't have the class of the W116.

Is it safe to continue to drive the car with a leaking head gasket?  Do head gaskets suddenly blow out all together causing massive engine destruction?

The $4,500.00 head gasket job consists of replacing the head gaskets and doing a valve job as well. The hourly labor charge is $80.00 per hour thus the high cost.

If I can continue to drive the car, without ruining the motor, then I guess I should keep it and just monitor the leak until I can get the gaskets replaced.

With all of the work that has been  done over the last three years it is almost like having a brand new Mercedes. It would be a shame to sell it now.

 

[koan]

Can't be sure but I doubt the leak would suddenly let go.

If it did let go and all oil was lost the engine would suddenly be very noisy, that would be the signal to stop immediately. A few seconds running without oil won't do any engine damage.

Watch the oil level, carry a couple of litres (pints, quarts?) with you and watch the oil patch on the ground.

You must STOP immediately the engine becomes noisy and the oil pressure gauge drops, early warning is oil pressure dropping momentarily when cornering.

STOP means STOP now. Add some oil and then continue

koan

[Niclas]

I had an oil leak on my boat engine. I just retigthened the head bolts and it has now worked fine for five years!

The heads on the M117 should be tightened in maximum two hours per side.

DON'T give up hope/
Niclas

[brettj]

Thanks for all of the encouragement! I picked the car up from the shop yesterday feeling a bit more confident about it. My mechanic said the leaks are minor and I should just leave the gaskets alone for now. He did discover another small leak in the transmission at the transmission pump. I've never heard of the transmission pump. I asked him if he meant the torque converter but he said no and that the torque converter is not leaking. Where is the location of the transmission pump? Anyway I was told to leave that leak alone for now as well as it too is minor.

The timing, dwell and the exhaust emission controls were adjusted and the car seems to be running smoother. My mechanic also put in some super type of carbon remover in the gas tank. He felt that the periodic skip I get from the motor was caused by something in the gas tank or a build up of carbon.

Unfortunately, I'm still getting the warm start stall issue. I'm sure it is caused by the electronic switching unit. Last night I  started the car and as usual it turned over but then the motor starts idling rough , the tach starts going up and down and the motor speeds up and then  slows down. As soon as I put the car in gear or hit the gas the motor stalls. I had to restart the car 4 times last night before it finally became driveable. I think that when the switching unit gets hot, it tries to cut the electrical current flow to the engine causing the stall. I want to put in the used switching unit I purchased but I'm afraid to do so because the part may be for a K-Jet system.

The motor also did not leak at all over night. Perhaps the oil is starting to clog up the holes in the head gaskets? Is that possible once the head gasket is damaged?

[brettj]

I've noticed a slow down in the leak of my head gaskets. I changed the oil on Friday and installed regular old 10W 40 oil. In my last oil change, which my old mechanic did, he installed diesel oil. Since I replaced that oil with 10w 40 the motor has hardly leaked. Could the diesel oil been the cause of the leak in the first place? You would think the thicker the oil the less chance of leakage.

[oscar]

In my last oil change, which my old mechanic did, he installed diesel oil.

Why did he do that?  Did he sell you on the idea that it'd be beneficial for a short time?  Of all the interesting oel threads I've read stuff about diesel oil being high in 'detergents' and can be good to use as an engine flush but not for constant use.  Major Tom tried some I think a while back??  Problems can occur with overcleaning with deposits being dislodged and blocking up oilways, less protection for journals and bearings, and gaskets may leak....or so I've read and I also read somewhere about cat converters being affected too but I can't remember why.  I suppose they become blocked.

At least you've changed it now but I think there's some plausibility to the thinking that this oil could've contributed to seal leaks.
How many miles had you done with that oil?

[brettj]

The reason for using the diesel oil was that it is thick and would help to seal up any leaks the engine may have. I told him not to use it but when I picked the car up he had installed it anyway. I ran the motor with that oil for about 1,000  miles. Hope I didn't do any damage to the motor internally. If the diesel oil did effect my headgaskets, now that I have the correct oil in the crankcase can the gaskets re-seat themselves ending the leaks?

[oscar]

I reckon regardless of how thick the diesel oil was I don't think it would help block leaks due to it's detergent properties.  A thicker motor oil would have been more effective.  At least the leaks have started to slow already and I think that it is possible that gradual build up of deposit can help block the leaks.  I'd go thicker motor oil again if the leak opens up again.  1000miles on the diesel oil is a bit much I would've thought but if you're not getting any bottom end noise or haven't sprung mad leaks I wouldn't worry too much.  Time will tell I suppose but I'd go about my business now that you've got proper oil in there.