Finally got another diesel Benz - PeachParts Mercedes-Benz Forum

ImBroke · #1 04-28-2018, 11:36 PM

Drove to Vermont (4.5 hours) to get this 350 SDL. My first 603, should be interesting. Bought it knowing it needed a power steering pump, so I got that before I even got the car. Put that in tonight after I got home. Car is still on the trailer, in fact. When I was strapping it down, I got a good look at the underside. Nice and solid. There is some small spots of surface rust, which I will take care of. Rear window is not delaminated. Supposedly everything works except the radio. I will check that out tomorrow, if it's not raining. After I get it home, seller tells me it will probably need a head gasket.. This is not sounding good. I will have to find out what head it is, of course. Hope it's just a gasket. Oh,, anyone got a factory air cleaner? You guessed it, someone put the stupid cone air filter on it, and the overboost control switch has been bypassed.

dieseldiehard · #2 04-28-2018, 11:44 PM

congrats on the SDL!
I presume you read up on the rodbender syndrome?
You need to have the head inspected for cracks first then surfaced and pressure checked while its off the engine.
I had a 350SDL and sold it after it was draining my bank account. Until a week ago I had an aircleaner housing but its gone to the dump now.
put a WTB on the parts section and see if David Hendy has one.
GL with the project!
DDH

Diseasel300 · #3 04-29-2018, 12:27 AM

What makes you think it needs a head gasket? The 3.5L doesn't have the head issues that the 3.0L had, but they have issues in the bottom end. As mentioned above, they have a reputation for bending rods and ovaling cylinders.

sixto · #4 04-29-2018, 12:59 AM

Any 602 or 603 is subject to head gasket failure pouring oil into #1. A 603.97 (3.5) should have a #17 head casting so if it needs a head gasket, that could be all it needs. While the head’s off, check piston protrusion above deck fore and aft. Any piston that sits lower in front/higher aft has a bent rod (see my avatar). I haven’t heard of a 603 rod bending aft but I suppose it’s possible.

Sixto
98 E320 sedan and wagon

t walgamuth · #5 04-29-2018, 07:16 AM

Welcome back! Hope the new car works our for you.

ImBroke · #6 04-29-2018, 07:35 AM

Quote:

Originally Posted by Diseasel300

What makes you think it needs a head gasket? The 3.5L doesn't have the head issues that the 3.0L had, but they have issues in the bottom end. As mentioned above, they have a reputation for bending rods and ovaling cylinders.

The guy I got it from says there gets small amounts of oil into the coolant. I know about the ovaling of the cylinders. I will check that if or when I do the head gasket. I didn't buy it for a project car, I have enough of those. I just looked,, #17 head. That's a plus.
Tom, that truck is looking sweet.

t walgamuth · #7 04-29-2018, 08:20 AM

Thanks! The 350s if having the bent rod syndrome will have an uneven idle. OTOH if its not bent too much you might replace the gasket and go a lot of miles without much trouble....as long as you don't mind the uneven idle.

ImBroke · #8 04-29-2018, 10:34 AM

Idles rock smooth, and hardly any blowby to speak of. If it quits raining, I am going to do a compression check to see how that looks.

ImBroke · #9 04-29-2018, 05:37 PM

This is why it needs a head gasket. No bubbles, so it's not blowing compression into the coolant, but oil is getting in there somehow. Second pic is after cleaning out the reservoir, and driving about 2 miles.

okyoureabeast · #10 04-29-2018, 05:39 PM

Quote:

Originally Posted by ImBroke

The guy I got it from says there gets small amounts of oil into the coolant. I know about the ovaling of the cylinders. I will check that if or when I do the head gasket. I didn't buy it for a project car, I have enough of those. I just looked,, #17 head. That's a plus.
Tom, that truck is looking sweet.

I like how our definitions of "project car" are so wildly different. A car needing a new head gasket to me fits the definition of a project car

t walgamuth · #11 04-29-2018, 08:16 PM

Could be a radiator leak, though that looks more like engine oil. No harm in taking a compression test but it might not reveal the problem.

The oil looks gray rather than pitch black...not sure if that is significant or not.

MB140300SD · #12 04-29-2018, 08:39 PM

If it needs a head gasket, that sure seems to fit the definition of a project car to me. Looks like it is leaking oil into the coolant pretty bad. While the head is off, measure how far above the deck the #1 piston is sitting as compared to the rest. It should be just slightly above. If it is flush or below deck level, rod is bent. If that is the case, rotate engine so #1 is at the bottom, you will probably see the cross hatch worn off the front and back of the cylinder, and still visible on the sides. This indicates that its ovaled. You will then need to measure the cylinder to see if it is still within spec or too far out. If its still in spec, replace the rods and you should be good.

ROLLGUY · #13 04-29-2018, 10:16 PM

I had to replace the head gasket in my 350SDL at about 120,000 miles. It too was getting oil in the coolant. As said above, surface and pressure check the head. After a good cleaning, be sure to check the block deck with a precision straight edge and feeler gauges.

dude99 · #14 04-29-2018, 11:04 PM

Be sure to source the new gasket ONLY FROM MB!!! I have done a lot of reading on this when I was looking into buying one, it seems the aftermarket ones don't have the updated design that the MB ones do. Not a job you want to do twice.

torsionbar · #15 04-30-2018, 12:20 AM

Quote:

Originally Posted by okyoureabeast

I like how our definitions of "project car" are so wildly different. A car needing a new head gasket to me fits the definition of a project car

Ha, was thinking the same thing! Oil in the coolant, bad power steering pump, some rust needs cleaned up, that's a "project car" in my book.

Exterior looks in decent shape, although I would remove those aftermarket chrome wheel arches as they like to trap moisture and hide rust.