Engine troubles

[Scop]

It all started yesterday. I went to to start the car from hot and it started to chug on idling, with a few revs it got better and drove fine. This morning it did it again from cold this time and then again from warm. I then phoned my indy and booked it in for a look.

Anyway just now, I set off to the tip and noticed the coolant light had come on and then noticed smoke coming out of the back !! I turned round and returned home. Doe this all point to the dreaded Head Gasket ? The engines too hot tocheck right now so I'll have a look later.

Could anyone enlighten me ?

Cheers

 

[Scop]

Right, I've just checked. The coolant has all gone ! It was fine recently. As far as I can see theres no mayo on the oil filler cap, the oil level on the dipstick looks fine too. The oil pressure was at 3 when driving and 2-3 when idling. I wonder if its just a coolant leak and because the engine had got really hot it just burned the oil ? I'm no mechanic as you can probably guess !!

But what would explain the rough running at startup ?

 

[flyingtech55]

Hi Scop

Head gasket failure I'm afraid. It fails at the back of the engine generally at number four pot. It starts by leaking cylinder pressure into the water jacket and pressurizing the cooling system. This often blows the coolant out of the cooling system. After a while the pressure stored in the cooling system forces water into the cylinders when the engine cools down after a run. This is why the engine runs rough when you start because there's water in one or more cylinders when you start the engine. If you catch it early before it looses all its coolant and overheats you can generally get away with just renewing the head gasket. This was the case with my 190. Because I am able to do the job myself, I was able to catch it before it cooked up and simply renewed the gasket, head bolts and the 'stat. That was 5000 miles ago and all is still well thank goodness. However, if the engine has overheated, and it sounds as if yours has, or if it is being done by a garage as a chargeable job, the head will need a skim because it will probably have warped.

Good news is that it is not too difficult to do if you are doing it yourself and because it is a common problem, an indy will have done the job many times.

HTH

Gliderman

 

[Scop]

Many thanks flyingtech. The cars off to the garage on Wednesday. I'm not sure if it overheated or not as the temp gauge didn't get all that high. Am I OK to drive it a couple of miles to the garage ? (I'll top the coolant up first !)

Would you recommend getting the valve stem oil seals replaced at the same time, would this add much to cost as the head will be off anyway ?

Regards

 

[Scop]

Confirmed this week as head gasket failure ! Around 650 inc to fix plus extra for skimming.

 

[Scop]

Update

Got car back after £850 bill (650 for gasket job plus 200 for skimming and welding corroded head).Driving beautifully until the oil light came on !

In 250 miles it used a sumpful of oil !! No leak detectable at idle but indy reckons it might be timing chain cover gasket this time. Should they have replaced this whilst doing the head gasket ? Or are the two completley unconnected.

I could do with an answer today as I am collecting the car tomorrow and hope I don't get charged fully for it !

Thanks in advance

 

[television]

Changing the head gaskit always requires special care in the area of the timing chain cover at the top.

The thing is here that you have lost 5 liters of oil, where, that would make a mess on the engine or the ground, was it full after the repair ? something here does not add up.

Malcolm

 

[Scop]

Thanks Television, yes it was full after the repair. Basically it seems to spray out oil when the car is being driven and does not do it when stationary. The oil colects on the undertray and dribbles out all over the road when parked up. The indy thinks it may be the timing chain cover gasket. What I am getting at is does the timing chain cover come off during the CHG repair and if so should the garage have replaced the timing chain cover gasket during the repair ?

 

[television]

The thing here is that it does require care when doing the job
Please see the thread. its down to the one doing the job to do it correct.

http://www.mercedesshop.com/Wikka/M104HeadGasket


Malcolm

 

[flagstaff]

one does not weld a 'corroded head' (whatever that means). any damage to the head that cannot be rectified by skimming should be identified at inspection and/or measurement, and reported accordingly.

i think these guys are funning with you.

 

[Scop]

Television

Thanks a million, thats an excellent article. It seems they may have tried to work with a perished timing cover gasket in which case they should have spotted it and replaced it as a matter of course or they simply didn't get it seated properly. If they are fair I think they should cover the bill ! I was a little perturbed about the timing chain tensioner failing once its been removed, is this another nasty waiting or would fail instantly ?


Flagstaff

The corrosion is something to do with the cast iron block reacting with the alloy head and the wrong or too little antifreeze being in the system (apparently !)

I'll update once I get the car back

 

[Scop]

Final Update (I hope)

Leak was confirmed as timing chain gasket (u shape gasket) which they replaced for no charge (hooray). I noticed the odd spot of oil dropping after parking up but I reckon it was just oil that had collected on the undertray during the leaking, it seems to have stopped now. Car sweet as a nut now. Since the CHG was done the gearbox changes down much more readily, is this because the throttle linkage would have been readjusted ?