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Model: Mercedes Vito 638 108 CDI, 2.2L, 1999

Mileage: 270,000 Km.

My exact question is: Does my head gasket need to be replaced (is this the source of my problem), and is this the ONLY problem wherefrom I am having these symptoms (or did I for instance crack some part of the engine by driving in the heavy rain)?


Symptoms Summary:

  • Tiny bubbles emerge from cooling liquid when pressing the accelerator pedal

  • Cooling liquid level decreases while driving and has to be topped on

  • Oil level erratically increases after having driven (going from near minimum level to near maximum level). Hard to foresee / accurately reproduce.

  • Oil Smells of Diesel

  • Diesel consumption seems a bit high

Absent Symptoms

  • There is no mayonnaise, whether in oil or cooling liquid. Oil looks fairly normal, except maybe a bit thinned down by diesel.
  • No particular smoking from the exhaust, even in winter. Once upon starting it in the middle of winter (maybe -3C), after having been idle for months, it made a huge amount of smoke (like a small smoke screen), which stopped after a minute or so of running, and then no smoke at all (like a perfectly normal car) when driving for 30min.
  • The engine is not running hot. It slowly settles to 80C while driving and then stays there, no matter how long, how fast or slow I drive.

Preceding Symptoms:

  • I was made aware of the issue when finding myself at a garage due to a diesel leak. It turned out to be one of the little black (silicone?) tubes on top of the engine that had cracked. These tubes I believe are used to carry away excess diesel from the injectors. I assume that it cracked because it became brittle with time, having sat there for 22 years. This was replaced by the garage (which very nicely did it for free) and I drove away, only to have a new diesel leak on the next day. The second time I did myself what I had seen the garage do, found that a second of the three black hoses had cracked, and replaced it, along with the third one which I assumed would crack as well in the near future. So now there are three new black hoses on the injectors. The only difference with the original ones is that the ones that cracked had some woven cotton insulation around them (which I thought is to shield them from the engine heat) and the replacements are bare, but the garage person assured me it doesn't make any difference.

Personal Notes: I initially thought that the hose cracking was due to a problem with the injectors, or them being "dirtied" by sooth, but the garage person told me the hoses most likely simply were too old.


The Whole Story:

I drove through a very big thunderstorm for an entire night. It was a wonderful experience and the road was almost completely free, except covered by water (with the headlights reflecting on the surface the road looked like a single very large flat surface with no markings on). I didn't think it was a problem to drive with a car in heavy rain, assuming cars were designed to withstand conditions that would normally be met by most drivers during their car's lifetime (I personally find myself driving in such rain once every 2-5 years) and never thought this could be linked to the problems I later experienced until reading this. The air filter under the hood is situated fairly high up, but definitely not as high as the splashes/waves on the sides of the car (every now and then the car would make splashes going up maybe 3-4 meters high on either side of the car, which I assumed by design only happened on the sides of the car and wasn't going up in the engine compartment / or at least not ending in the engine, which might have been an incorrect assumption).

In any case, the car drove well through the storm and it wasn't until a few days (and several hundred kilometers) later that I experienced my first issue: diesel would drip under the car upon starting the engine.

While it never even remotely occured to me it could have had anything to do with the rain, I searched the internet and ended up fearing the worst: that the diesel pressurizing pump or injectors would be faulty, potentially due to sooth accumulation (I've driven several thousands of kilometers usually staying in the 1500 to 2300 RPM range which upon reading I learned might be too low and detrimental to the engine).

Luckily (because I only had enough money to buy food for the winter) the leak culprit turned out only be the silicon retour tube. However the garage person told me I was starting to have an issue with what appeared to be the head gasket joint and that I shouldn't drive too far after that point. The diesel leak happened again and all remaining diesel retour tubes were replaced after which the diesel leak issue has been solved.

Left with the idea that my low RPM driving could have dirtied the engine, which would lead to higher pressure and potentially could have caused the tube cracking due to greater retour flow, I filled 20L of super high quality diesel (called excellium) and drove at 2500-3000RPM for 40-50 min. The coolant level however keeps decreasing, and the oil keeps smelling of diesel, with the level varying.

Since I don't have enough money to pay a garage to repair the head gasket (I was asked 1400-4300€ for the repair upon asking several garages), I've since then been living in the car in a forest and only start it every two months to go get water. This wasn't a problem at first because I had driven away to meditate in the car for awhile and the forest fit perfectly, but I'd now like to return the car, repaired, to its owner, and move on with my life. While I've found a garage that will lend me access to its tools/equipment, and if I'm lucky I can rent the support of someone well versed in car mechanics, as a retired car mechanic for instance, to assist me during part of the repair, I still have to fully diagnose the issue on my own (and in the forest) beforehand, buy all the parts I need beforehand (all parts I'll need + the right ones + good quality so they last for the car's owner), and probably do most of the job myself.

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    You could start by using a compression tester to test each cylinder.
    – HandyHowie
    Commented Sep 13, 2022 at 19:03
  • Thank you for your contribution. What should I conclude if a specific cylinder compresses differently from the others?
    – Hans
    Commented Sep 13, 2022 at 19:09
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    Either there's a crack in the block, or a head gasket fault adjacent to the affected cylinder(s), and/or a valve problem (wear or crack) in the affected cylinder(s). Rectifying any of those possibilities will require the head to be removed from the block. Commented Sep 14, 2022 at 1:41
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    I think the comments and answers point you in the right direction, instead of adding to that I am going to suggest you consider how much time, effort and money a 20+ year old van with 270k km is worth.
    – GdD
    Commented Sep 14, 2022 at 8:04
  • Thank you GdD. It is true that I don't think about this enough and I have a very poor notion about how much longer it can fare overall. There is a very non-technical aspect to it though: Someone very nicely lent it to me and I've had it far longer than initially expected and this occured under my use of it. I would very much like (to say it mildly) to hand it back in much better condition than I got it.
    – Hans
    Commented Sep 14, 2022 at 9:51

1 Answer 1

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From the description it could be a number of things:

  1. Blown head gasket
  2. Cracked block
  3. Cracked cylinder head
  4. Warped block
  5. Warped cylinder head

But of these the most likely is the head gasket. You have to pull the head(s) to get at the gaskets and while you are in there you can inspect for cracks and warps. In my experience, however, a head gasket problem is usually easy to identify once the head is off.

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  • Thank you very much for your answer! From the understanding I got from various repair shops it is particularily complicated to take appart the head especially on this car model (and I don't know if I can do this until the moment I am already in a repair shop ready to repair it with the parts and all, since I'll only have a limited time access). Is there anyway I can differentiate between the issues beforehand in the woods by doing some tests / manipulations with the car?
    – Hans
    Commented Sep 13, 2022 at 14:59
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    None that I know of. You check the block and head for cracks by inspection. You check for warps with a straightedge, you check for a head gasket by replacing it.
    – jwh20
    Commented Sep 13, 2022 at 15:45
  • Thank you very much for your help! You're awesome : )
    – Hans
    Commented Sep 13, 2022 at 18:43

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