I am driving the SDL in Oman (I shipped it over with household to Oman). It is maybe the only Diesel W126 here.
I am driving 80/90 mph on the highway and I am facing some problems I didn't have in the US (with 65 speed limits).
Ambient temps are 90 - 100 F at the moment. I have AC on at all times.
Typical cooling temps at lower speeds are 85C- 90C

Problem 1: Rattle:
Car (interiors and steering wheel) is shaking and rattling very heavily from 75 mph on. It is bothersome. I remember the car has done this before when I drove faster in Canada...so it is not new it just doesn't do it at low speeds.
Don't think it is the wheels . What might be the reason for this?

Problem 2: Overheating:
When I set cruise at 80mph cooling temps will go up to 100C , exhaust temps at 1000F average
If I set at 90mps cooling temps climb close to 120C !!! and exhaust temps at 1200F (average)

The car is going strong (with slightly open IP) and I can easily get to 1500F (and more if I want) but this would kill my pistons. It happens once in a while for very short times but I try to go beyond 1200F.

So I think I have a cooling temp. problem? I have the old radiator and the old pump installed but have new radiator and pump on my garage shelf if this solves the problem.


Please comment.
Martin

http://www.peachparts.com/shopforum/diesel-discussion/162793-om603-fan-clutch-upgrade.html

Also get a 71c thermostat.

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CENSORED due to not family friendly words

How dirty are the exterior surfaces of the radiator and condenser?

The oxidation catalyst might be clogged if EGTs are that high in level cruising. Or is Oman hilly?

Sixto
87 300D

You actually have to install them in the car to solve the problem...

Not the pump, just the radiator.

Straight water will transfer heat better then anti-freeze mix, but will boil at a lower temp. I am not sure where the trade off is between better cooling and higher boiling point, but you might want to try straight water in your new radiator as a test.

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Greg
2012 S350 BlueTEC 4Matic
2007 ML 320 CDI
2007 Leisure Travel Serenity
2006 Sprinter 432k
2005 E320 CDI
1998 SLK230 (teal)
1998 SLK230 (silver)
1996 E300D 99k, 30k on WVO
Previous:
1983 240D, on WVO
1982 300D, on WVO
1983 300CD, on WVO
1986 300SDL 237k, 25k on WVO (Deerslayer)
1991 350SDL 249k, 56k on WVO - Retired to a car spa in Phoenix
1983 380 SEC w/603 diesel, 8k on WVO
1996 E300D 351k, 177k on WVO

In the mid east - use a 30% coolant mix. Thats what most premixed coolant is sold in all those countries.

Clean out the condenser fins - You will experience dust storms there so intense that it will fully choke the fins - even in normal days the ambient dust can clog the condenser/radiator - experienced that.

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2012 BMW X5 (Beef + Granite suspension model)

1995 E300D - The original humming machine (consumed by Flood 2017)
2000 E320 - The evolution (consumed by flood 2017)

Hi Sixto,
I checked condenser...it seems fine. I cleaned radiator fins (a while ago) but I think condenser id more critical.
I removed the catalyst- too much resistance.

Oman can be hilly but on the test highway it is flat with a few minor slopes.
I have an aircaft exhaust temperature gauge installed.
Not sure why the temps are that high, it is scary.

The car had enough power to go 100MPH, I guess but I can't because of the temps and also the rattle kills me.
Martin

Yes, I am just not sure what brand. Some make a deal out of the mercedes coolant. For sure I don't get the Zerrex (or what is it called). I could try at a dealer. Does any Mercedes coolant do the job?

30% makes sense. I won't do just water because of boiling point of water and corrosion.
Martin

I have to correct myself

When I set cruise at 80mph cooling temps will go up to 110C , exhaust temps at 1000F average
If I set at 90mps cooling temps climb close to 120C !!! and exhaust temps at 1200F

This is frightening me quite a bit.

I can try and install the new readiator and see if it does something.

Can the exhaust temperature be true. I mean I have the reading on a proper airplane gauge. This gauge is reacting very fast. I can follow the gauge and see if I step on the gas instantly.

Yes, the exhaust temperature can be true. Is your air filter clean? Reduced air flow will increase exhaust temperatures.

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1977 300d 70k--sold 08
1985 300TD 185k+
1984 307d 126k--sold 8/03
1985 409d 65k--sold 06
1984 300SD 315k--daughter's car
1979 300SD 122k--sold 2/11
1999 Fuso FG Expedition Camper
1993 GMC Sierra 6.5 TD 4x4
1982 Bluebird Wanderlodge CAT 3208--Sold 2/13

Im sure there are some MB and Ford dealers in Muscat - get the conc coolant from them and cut it down to 30%.

Zerex G-05 is the coolant made by Valvoline (I believe Zerex is a BASF formulation). If you can locate a valvoline dealer there then they can get you that. You might run into a shop that calls themselves "dealer" - they would actually just be a bulk buy retailer.. Seen that too much - and TBH I hated it, it gets annoyingly bad.

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2012 BMW X5 (Beef + Granite suspension model)

1995 E300D - The original humming machine (consumed by Flood 2017)
2000 E320 - The evolution (consumed by flood 2017)

Hi Kerry, good call on air filter. I am driving since one year in this dry and dusty country. I need to check for the filter anyway. Easy.
I'll report back.

So you are saying the exhaust temps can be true? Good start.
Well I can get to 1500F within no time if I want. I am not even flooring it.

I have an open IP but no intercooler installed.
Before I opened the IP I had no gauge and so I have no comparison what the stock IP exhaust temps are: It would be great to hear.

What do people say: what exhaust temp is the red line for the 603 SDL?
Can I drive 1200 constantly (which I do sometimes...seems to work) or can I drive 1400F constantly? Can I go 1500 for a few seconds, 10 seconds , 30 second, a minute ...?
When are the pistons definitely melting?

Who has the experience?

I also guess that the glycol cooling system has not much or no effect on the exhaust temperatures. Am I correct?
That doesn't mean that I don't want to fix the radiator. I'll put a new radiator in, then see the difference.

For the fan: I doubt that the visco fan does a lot at high speeds?
There should be enough airstream by the high velocity?
Fan is more for idle in traffic?
What do you say?

Zulfiqar: Is Ford and MB using the same coolant type?

This might be a chicken or the egg situation - are high EGTs causing high coolant temps or vice versa? I'm tempted to think EGT has more influence on coolant temp than the other way around. An ineffective cooling system can cause high CHTs but not high EGTs. My neck's out there, chop away.

Have you checked IP timing? For kicks, remove or shim the ALDA to see if more fuel helps. Do you have a boost gauge to see if you're blowing more than 1 bar.

FYI - there was some discussion about MB changing coolant formulation just this year. When stocks of the old formulation (G05) are exhausted, US dealers will sell blue coolant (G48) which is supposedly backward compatible with the old stuff.

Sixto
87 300D

Sixto,
I agree with 'EGT has more influence on coolant temp than the other way around".
If my EGTs are 'normal' or not I can't say.
IP timing is about 1 degee advanced (15 degrees with the light if I am not mistaken). I have an open IP. I have plenty of fuel!
Boost...no gauge but I have a regulator and I think I run slightly higher pressures than stock..I'll check my records.

Coolants:I can buy aftermarket cheap stuff (some say Mercedes on the bottle ) or I 'll try to get coolant from the dealer.

High Cruz'n = Higher speeds in hot climates

Re wheel vibration...you need great tires and a true high speed balance job. w126's are just very needy that way.

Re: Engine temps...do what these guys are suggesting +:

Make sure your exhaust flow is primo i.e. install test straight pipe where the "Cat" is. Not a true cat converter but it cloggs up resulting in high exhaust temps. (don't toss the "cat").

Think about adding an exterior trans cooler. Transmission heat transfer to the motor when jetting along at 80+MPH is a real thing

See what an MB Tropical T-stat i.e. 60* or 70* will do for ya. I love this addition to my cooling system.

& in my experience ya need a good new fan clutch. A marginal one is trouble....and I find that my 603 needs that fan yanking / directing air though the radiator even at 80 mph.

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1986 300SDL 440,xxx