interesting engine degreasing find - PeachParts Mercedes-Benz Forum

JHZR2 · #1 01-20-2004, 01:37 PM

Hi,

I am interested in getting oil that has dripped from my filler cap to the #1 and 2 injectors, drip from around the injection pump, and also the turbo oil drain tube clean, and then degease the underside, where all thoise drips and dust, etc stick.

I also own a BMW, and found that the 'official' instructions (http://www.sts.sae.org/servicetech/nov-2001/bmw.htm
) for it is to NOT use any sort of steam degreasing, but to instead warm the engine to full operating temp, apply a degreaser, then rinse with [warm] water.
I am curious about this for our 617 diesels.

I live in an apartment without any car washing facilities. The closest carwas is about 7 miles away. No matter how easy I drive, the car will be up to temp by then. I worry about even if I let it sit for 30 minutes, that things like the IP and manifold will be hot, and the sprays can crack such items.

At the same time, when driving in hard rains, I have to imagine roadwater gets splashed up on some of these things, while driving at full hot temperatures.

So is it OK to lightly spray water onto stuff like the valve cover, IP, block and oil pan if the engine isnt fully cold, or even if the engine is at full coolant temp? Apparently BMW thinks its OK, and gasser engine exhaust manifolds, etc. ought to be hotter than our diesels.

Any info would be appreciated.

Thanks,

JMH

lrg · #2 01-20-2004, 02:03 PM

In general you are trying to keep from subjecting the engine to sudden, extreme temperature changes. Cold water on a warm engine is not good, neither is warm water on a hot engine. You're probably safe though with cold on a cold engine or warm on a warm engine as long as the relative temperatures are not very far apart. If you see steam rising when you rinse STOP! On occasion I have used Simple Green on a warm engine (not hot as it will all evaporate and do little good in cleaning) then rinsed with a few buckets of hot/warm water without harm. You especially don't want to douse the IP with cold water from the hose unless the engine is stone cold. The more precision the part, the more susceptible to damage from sudden temp changes as the different metals rapidly expand/contract at different rates. Also be careful of areas that tend to be hotter than the rest of the engine, like the exhaust manifold. Your bucket of warm water may be fine on the block but cause a problem when poured on a much hotter exhaust manifold. Just exercise a little judgement with the above in mind and you should be OK.

Lars · #3 01-20-2004, 02:06 PM

I just recently hit a snowdrift that was across the road in whiteout conditions. The drift was about 3 ft high. Car didn't stall but all the engine lights came on, to eventually come off a few miles later. I opened up the hood when I got to work and saw that snow was packed around the engine compartment up to about the IP. Didn't do any harm to anything.

lrg · #4 01-20-2004, 02:22 PM

The amount of heat transfer from a stream of cold water (Garden hose) poured directly on an IP versus a splash of cold water or a pile of snow that almost instantly melts at the contact surface is very different. The soaking from a hose is a very effective heat sink. That said, these are pretty robust engines so they're not likely to have a problem unless you are really careless.

#5 01-20-2004, 07:44 PM

I have cleaned at least15 diesel engine {MB}. With spray cleaner, like Gunk. It is basically Kerosene. Then used a car wash to wash it off.
All of this {don't do it hot} theory is just that.
If these car are that delicate then the next time it rain's better pull over the water may damage the pump.
This is up there with ether will damage a pre-chamber thinking.
Can anyone say that cleaning the engine or using ether has caused damage. And show pictures or repairer receipt to prove it.
We are working the machinery hard by keeping it cover with oil.Plus harder to spot leaks.
Charles Mitchell

190D22 · #6 01-20-2004, 09:32 PM

I agree, but I would try to keep water away from the electical parts. They obviously CAN get wet... but be careful to keep the water to a minimum on the electrical stuff. On a gasser I'd be concerned with the entire ignition system... But we don't have to worry about that nonsense here!

Tirebiter · #7 01-20-2004, 09:47 PM

I believe that Mr. Mitchell is asking for first hand knowledge of damage to our precombustion chambers from using starting fluid or damage to our MFI pumps from washing them down with water
when they are hot/warm.
Anything less than first hand information is hearsay.
We have some very sharp working techs on this board as well as some very bright and logical novices (or non professionals if you prefer) that share their experiences with us. For that, we should all be grateful.

bodyart27 · #8 01-20-2004, 09:56 PM

try a new oil cap for the valve cover and an updated breather tube and that will help with your leaks.... as for the oil return under the turbo - you just have to replace that to make it stop making a mess

for more engine detailing stuff - this might help as well (I wrote this article for the nissan guys)

http://www.se-r.net/car_info/clean/detail_engine.html

here are some more diesel engine pics:

http://www.peachparts.com/shopforum/showthread.php?threadid=79692

http://www.peachparts.com/shopforum/showthread.php?threadid=79278