oil in coolant recovery - PeachParts Mercedes-Benz Forum

JHZR2 · #1 09-23-2002, 09:38 PM

Hi,

I notice some oil in the coolant recovery bottle, floating around the top... Not good. A head job according to the dealer is $3000 and up, and I dont have the tools/space to do it at my apartment. However, I am looking at a 1968 200, which smokes at startup, I believe due to dried out valve seals. In researching the smoking, I have read that if a car overheats, the head gasket can shrink and then especially at high running temperatures, can cause a loss of coolant into the cylinders, causing smoke.
My car has gone above 100 a couple times this summer while driving in 95 degree heat, at 75 mph with AC on... Could it possibly be that the head gasket can shrink in such a way that pressurized oil can seep into the coolant at a very small rate?
Theoretically, I guess it is possible, just wondering if anyone has ever heard of/seen this before. If that is the case, I guess it isnt really seriou, so long as I watch the temperature and pull off the oil in the recovery bottle from time to time...

The car doesnt loose coolant, barely any oil, and runs strong, starts up in less then 2 turnovers of the starter motor.
Any info is appreciated.
Thanks

JMH

#2 09-24-2002, 05:30 AM

What color is the oil???

Billybob · #3 09-24-2002, 06:29 AM

This might be premature and definitely short notice , but this head on Ebay might be a timely investment if you anticipate a future/ imminent valve/head project. You might be able to pick it up cheaper, ahead of time, have whatever done that may still be needed, and do a quickie swap job rather than having you car down while you drag the head to the shop and back for inspection and whatever work. Rebuilt heads seem to run from a low of maybe $300 and continue upwards depending

If it turns out your head is good and you don't use this one you could just turn around and put it back up for auction!

http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&item=1860268971

If you've had the car awhile and you are just now noticing the problem it would seem logical that some failure is underway and if you accept the inevitable repair scenario there's no time like the present to start acquiring the resources to do the job completely and competently. If you are planning on keeping the car a while you will want the piece of mind a good job ensures and you will enjoy the satisfaction of having mastered the skill, knowledge, patience, and perseverance that success will require. Good Luck in any case!

Do a search of MarkM's threads and you'll get an interesting picture of where such a journey might take you!!!!!

From:
http://www.peachparts.com/shopforum/showthread.php?threadid=31012

To:
http://www.peachparts.com/shopforum/showthread.php?threadid=38392

and plenty in between, lots of commentary and specifics.

#4 09-24-2002, 07:00 AM

With the car running well, you need to just remove and clean the overflow tank, put it back in place and monitor it. These are iron head engines, and 100 degrees will not hurt them at all. In fact you can seriously overheat them and probably not cause any head gasket problems.

If it ain't broke, don't fix it.

Good luck,

JHZR2 · #5 09-24-2002, 07:23 AM

The oil is its usual dark black color. No coolant has gone into the oil, I know this, because I keep a close watch on the level, and it is always at the cool water line.
The oil is not just a few specks, which Id think is kind of normal, it is actually dime sized circles in the bottle. They arent as black, more of a dark brown color (gues the soot setles out?

Thanks everyone for the tips/info, I really appreciate it.

JMH

#6 09-24-2002, 09:49 AM

you may want to verify that you don't have an internal leak in the trans oil cooler before you do anything drastic to the head. ATF should be reddish, but if the trans hasn't been serviced for a long time, it may appear black when floating on coolant mix.

#7 09-24-2002, 10:03 AM

Yes Fit is right on. If it were engine oil it would most definitely be black. It is almost certainly from the transmission. Remove the radiator and have it pressured tested at the radiator shop.

Do not take a chance on this because the least little antifreeze in your A/T will destroy the clutches.

Good luck,

JHZR2 · #8 09-24-2002, 10:18 AM

Thanks for the info, I just want to get this straight... You mean that the radiatior also has an ATF cooler in it too???
How hard is it to install a new radiator without putting the car on a lift?

I have thought it was slightly red/brown, and so may not be oil... Better check the ATF level...

Thanks
JMH

#9 09-24-2002, 12:04 PM

If you're talking about the 300D, then you probably do have a liquid to liquid heat exchanger in the bottom of the radiator to cool the transmission fluid (my '85 300TD does, and so do most cars nowadays), and it seems likely that you need to get that fixed and probably have your trans serviced ASAP.

The radiator should come right out the top once you have undone the shroud (and flopped it back over the fan), the top radiator mounts, and the many large and small hoses -- the small ones at the bottom will gush some ATF, so if you're planning to reuse your coolant because it's fresh, get that all drained and the pan out of the way before you undo the ATF hoses.

My older son also has a '91 318i, but with 215,000 miles -- I've got to do a clutch on that one at Christmas time.

#10 09-24-2002, 12:07 PM

Every car manufacturer that has an automatic transmission, has some sort of oil cooler for the transmission. Most all of them have a cooler internal to the radiator.

On MBs, the oil cooler is in the bottom tank of the radiator. The two small lines coming off of the bottom of the radiator are for the transmission. Typically when the oil cooler ruptures coolant goes into the trans fluid. If you find that your transmission fluid is a creamy pink or creamy brown color....well....find another transmission. All auto trans manufacturers use a water based resin to hold the friction material to the clutch plates in the trans, but when water or coolant gets in there it softens all that resin.

But it depends on which has more pressure. The trans cooler circuit typically is 15-30 psi, and the coolant system pressure is typically 15 psi.

Check that trans fluid!!

JHZR2 · #11 09-24-2002, 02:23 PM

once when I checked my trans fluid, it always was slightly foamy looking (air bubbles) despite being the correct level. Could this be vaporized coolant or something like this?

If I replace the radiator myself, and start leaking out ATF too, any ideas how much ATF Ill need to add back in? Ill use mobil 1... Transmissions are tricky to fill, especially the 300D, as the fill is through the dipstick. I dont want to screw that up...

Maybe its best to do this at the dealer/indy/local garage, seems like there is the potential for this to be really messy...

JMH

#12 09-24-2002, 03:36 PM

When you change the radiator, you need to CHANGE the ATF. I don't know how much it will take, but somewhere around 6 or 8 quarts.

The radiator on the five cylinder is not real easy to get out, but it doesn't have to come out the bottom. On the four cylinders, you can have the radiator out in a few minutes, the longer five cylinder makes it a wrestling match.

Good luck,

#13 09-24-2002, 04:29 PM

I just did a radiator replacement on my 83 300d because of a crack in the top plastic. It was about as easy a job as I have ever done on the car. Total time took about 45 minutes. Tranny oil lost was about 8 oz.

JHZR2 · #14 09-24-2002, 04:37 PM

rebootit--

Thanks,

Any tips on the process? I think Ill be doing this soon...

JMH

dieselcruiserhe · #15 09-24-2002, 04:38 PM

Every car, gas or diesel I've had has had some sort of goop in the radiator overflow container at some point. I've seriously cracked / blown a head gasket (never took it apart) on an engine before and can describe the symptoms:

1) Noticable "use" of coolant as it is being combusted hence the smoke.
2) WHITE smoke from the burning of coolant, possibly lots of it.
3) Gurgling in the heater / vents area from air being trapped in the coolant system due to the leak.
4) With mine, at first it started as a small white cloud from when the engine would start. Within a few weeks the truck was spewing out large amounts of white smoke for the first 20-30 seconds of running, then it would go away. This is not always the case but I've heard of similar symtoms.
5) Coolant in the oil.
6) Ironically enough it never ran greater even with the cracked head, just smoked badly at startup no matter if the engine was hot or cold.

All this was on a gasser but I couldn't see what the difference would be other than maybe changes in the amount of smoke.
Hope it helps, if your engine's head is iron then you're probably fine, sounds to me like no big deal.