Car: 1997 W210 E320 165K miles, good condition

Symptoms:
* intermittent coolant leak, appears to be from rear of cylinder head
* oil leak from rear passenger side of head, under exhaust manifold
* coolant temp spikes when vehicle is stopped or parked, though it doesn't overheat
* definite oil film in coolant reservoir
* no foam or coolant on dipstick ???
* vehicle drives fine otherwise

My diagnosis: Possible cylinder head gasket failure???

This is a friend's car. He called me the other day as there was a large liquid leak under his car. I walked him through checking it out over the phone; the leak wasn't coming from a hose or the water pump. I had him dab with paper towel and he indicated it was straw color (coolant). The reservoir was low but not empty, and he said he could see drip drip drip towards the rear of the engine. He assured me the A/C wasn't on. I had him top up with water and drive it over to me.

By the time I got it, the water level had dropped again, and there was a puddle under the car, though the level was still acceptable. With jug of water in hand, I drove it about 30 miles observing its behavior. The temp would climb sharply at a stoplight, and the A/C vent output would become notably warmer, but the car never overheated. Aux fan works properly (I replaced it for him last year, so it is new). Belt driven fan also works properly.

Here's where it gets confusing - I parked it in my driveway and went out to check it the next morning. Sure enough, there was a puddle of coolant toward the back of the engine, and the level was much lower. I topped up the reservoir and started the car but could not get it to leak again. I let it idle for 45 minutes, even drove it around the block a few times, and up and down a local road, and it got hot (though never overheated) but again I just could not duplicate the leaking condition. I have driven it on and off now for the last couple of days - the last time was yesterday at lunch, and it hasn't lost one drop of coolant!

Experts, please correct me if I'm wrong. I am 99 percent sure this is a blown head gasket, but since the coolant has stopped leaking I can't be positive. A few questions:

* isn't the M103 (like in my 300E) very prone to cylinder head failure but the M104 is more robust and therefore immune to this issue?
* due to the channel design of the head, shouldn't a gasket failure lead to oil leak rather than coolant leak? I can see an oil slick along that side of the engine, but it is just not enough to create the garage floor puddles supposedly associated with a head gasket failure.
* I recall reading here that it is safe to drive on a bad gasket for a long time, as long as you didn't mind the mess, but that there was no inherent danger to the engine. As I find oil sludge in the coolant reservoir, I argue that this can't be good for the engine. If oil is getting in the coolant, then eventually coolant will get into the oil which will kill the bearings. Am I off base here?

A little bit more background info, I replaced his aux cooling fan late last year as the car was overheating in stop-and-go traffic and the A/C was cutting out. I recall when I met up with him, the temp was spiked in the red (yikes!) and I hurried to have him shut it off. Is it possible this type of on-and-off overheating led to the gasket failure?

The worst part is, I am almost certain this problem will reoccur the minute I give the car back. Even though I can't duplicate it here in my driveway.

P.S. - the tranny shifts fine, I already suspected mixture in the radiator. The radiator is in excellent condition, so I don't suspect a failure. I may have to drain the tranny fluid to be sure though. I'm just trying to avoid the added expense to my friend.

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08 W251 R350
97 W210 E320
91 W124 300E
86 W126 560SEL
85 W126 380SE Silver
85 W126 380SE Cranberry
79 W123 250
78 W123 280E
75 W114 280

Based on my recent head gasket experience, I can tell you the following.

The M103 and M104 series engines are plagued with the head gasket issue. They manifest themselves in slightly different ways however. Typically, the "oil in coolant tank" issueis an M103 symptom, but I suppose it can occur on the M104.

Leaking at the rear of the head occurs on both, although mine breached at the front.

Oil leaking is profuse when it lets go. Performance is unaffected, but how much oil leakage you can tolerate is your call.

As far as discovering coolant leakage issues? Here's my theory. The combustion pressures are far higher than coolant pressures, and when the head gasket lets go, the combustion pressures now increase coolant pressures. This probably shows up as "running hot" when the car is idling at a stop or something...I witnessed this with mine.

Extended high pressures with the cooling system will cause the weakest link in the system to fail...in my case, the large heater hose near the rear of the engine. It started out as a tiny leak, and I was filling the coolant tank every month or so. Eventually, the leak got larger and I was filling it up every other day. Finally, it ruptured, and by sheer luck I was able to limp it home with no adverse effects.

Your assessment of a head gasket leak is pretty accurate, IMHO. I got mine done by my indie a few months ago, and based on what's involved, I understand the cost of labor...

__________________
2009 ML350 (106K) - Family vehicle
2001 CLK430 Cabriolet (80K) - Wife's car
2005 BMW 645CI (138K) - My daily driver
2016 Mustang (32K) - Daughter's car

Thanks G for the confirmation. I just now recall reading about your very similar head gasket experience. Can I ask how long you drove on it before it became unmanageable? Did you ever detect coolant in the oil?

I am going to call and get some quotes, but there is the possibility that I may end up doing the work for him. In the past, when I have done cylinder heads, there were a lot of other things that I did at the same time because they were much easier to get to while the head was out. These included hoses, connectors, water pump, front cover, valve guides and seals, etc. especially if these parts were original. Since you have gone through this already, what would you recommend be done while the head is out? Also, can you tell me if you removed the manifolds or if you left them intact and removed the whole assembly with a hoist?

One last thing - I fear the wiring harness and other delicate parts may not survive the procedure. Although the deteriorating wiring harness issues were supposedly resolved by 1995, I checked his out and it appears that years of heat have dried it out and made it brittle. There are a few wires in fact that I swear I can crack the insulation if I bend them enough. Did you run into any issues with your harness? Any electrical gremlins after the job?

I'm trying to weigh the pros and cons so I can make a recommendation to him. I would hate to get started only to find out that the cost of repair exceeds the value of the vehicle. I know that harness can be expensive! Thanks.

__________________
08 W251 R350
97 W210 E320
91 W124 300E
86 W126 560SEL
85 W126 380SE Silver
85 W126 380SE Cranberry
79 W123 250
78 W123 280E
75 W114 280

Oops - sorry, I must have missed this. Do you mind me asking how much you paid to get it done? Also, which indie (you can PM me if you prefer)?

Thanks a bunch!

__________________
08 W251 R350
97 W210 E320
91 W124 300E
86 W126 560SEL
85 W126 380SE Silver
85 W126 380SE Cranberry
79 W123 250
78 W123 280E
75 W114 280

By the time I got this fixed, I was leaving what looked like a pint of oil on the ground wherever I parked. I planned to live with it until the summer, when i was going to tackle it and my ailing tranny. I was not getting any oil in the coolant, but I started to lose a lot of coolant in shorter and shorter intervals, until I had to fill the tank each day. The heater hose burst, which is when I had the car towed to my indie for the head gasket.

As you can see from the earlier pic, lots of stuff accessible with the top end off the engine. I would recommend replacing anything and everything that looks suspect, and that is exactly what my indie did. My coolant pump was fine, but he did replace the tensioner, fuel injector seals, and plugs. Of course, the busted heater hose was replaced. There were a few other little things replaced, but I have to go back and look at the list.

I wasn't there when the indie pulled the head, but he took the exhaust and intake assembly completely off (again, see pics). My intake manifold was cracked, and you wouldn't have seen the damage if it was just left in the engine bay.

No issues with the harness, although the indie looked at it and thought maybe in two or three years, it would need replacement.

My radio apparently was away from the battery too long, and wouldn't boot up after the code was entered. So I'm shopping for a new one.

Just yesterday, I noticed my oil pressure needle pegging upon startup...so I guess I lost the oil pressure sender...AGAIN!

The total cost of the repair was $2300 ($300 for the new manifold).

My indie is Don Borland of MB Haus 817-498-0075

__________________
2009 ML350 (106K) - Family vehicle
2001 CLK430 Cabriolet (80K) - Wife's car
2005 BMW 645CI (138K) - My daily driver
2016 Mustang (32K) - Daughter's car

My local indie replaced the head gasket on my old 1993 300E (3.2) for about $1,400, IIRC.

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Paul S.

2001 E430, Bourdeaux Red, Oyster interior.
79,200 miles.

1973 280SE 4.5, 170,000 miles. 568 Signal Red, Black MB Tex. "The Red Baron".

Wow - how can he make a profit at that price? Did that include parts? I'm assuming he did absolutely nothing other than replace the gasket? The 93 has an M104, right? I could see if it was an M103, but for an M104 that is a very good deal.

__________________
08 W251 R350
97 W210 E320
91 W124 300E
86 W126 560SEL
85 W126 380SE Silver
85 W126 380SE Cranberry
79 W123 250
78 W123 280E
75 W114 280

The total bill was about $2,000, but the original quote was $1,400 for just the head gasket.

The extra $600 included installation of a new throttle actuator (which I provided), and to have new valve guides and seals installed.

__________________
Paul S.

2001 E430, Bourdeaux Red, Oyster interior.
79,200 miles.

1973 280SE 4.5, 170,000 miles. 568 Signal Red, Black MB Tex. "The Red Baron".

Wow, again I say that is a really good deal. Probably about half what the dealer charges.

This is one of those things that I am thinking about. It seems to me that it would be almost stupid not to address the valves while the head is off, since it is impossible to do otherwise.

__________________
08 W251 R350
97 W210 E320
91 W124 300E
86 W126 560SEL
85 W126 380SE Silver
85 W126 380SE Cranberry
79 W123 250
78 W123 280E
75 W114 280

Exactly what I thought. I know that M104 engines are not known for valve guide / stem wear, but I thought it would've been stupid not to do it.

__________________
Paul S.

2001 E430, Bourdeaux Red, Oyster interior.
79,200 miles.

1973 280SE 4.5, 170,000 miles. 568 Signal Red, Black MB Tex. "The Red Baron".

My original quote was $1800, so $1400 isn't all that surprising if it was done years ago.

Also, consider that I had a laundry list of parts that were replaced while the head was in the shop, so that added up the tab.

__________________
2009 ML350 (106K) - Family vehicle
2001 CLK430 Cabriolet (80K) - Wife's car
2005 BMW 645CI (138K) - My daily driver
2016 Mustang (32K) - Daughter's car

I had the same head gasket problem at 75K miles of my '96 E320... , MB quality at its best, right???. My 200K 1987 Camry has been flawless , NOT a single day in service due to any kind of problems,,, just regular maintenance (change spark plugs and oil by myself, timing belt change at every 75K miles by my master mechanic etc...)

My MB indy charged me $1800 for head gasket job , refilled with 0W-40 syns oil (he said that the head surface was still super flat so there was no need to planarize it)... While U have its head open , you may as well replace the water pump if you have not done so.

Since my Camry is still going strong, my wife told me to "Buy anything as long as it's Toyota" , so I just bought her a new '07 6-cyl 4x4 RAV4, so far so very good

Don't get me wrong, I like driving my '96 E320 MB,,, but my next car is probably a Lexus... but I may not have that chance since I challenge myself to keep my current MB to 250+K miles... unless it nickles and dimes me to death before that... That means I will keep my '96 for the next 17 yrs because I drive only 10K a yr (I have '87 Camry, '94 Mercury Villager Van -wife's car- and new '07 RAV4)