Dave,

Yeah, I sure wish there was a way to capture that missing data in the poll. Thanks for rounding up voters from the roll-call thread.

About your Sis' car with the erratic temp problems, if you haven't done so, be sure to do the "roar" test on it to assure that the viscous clutch is in order. This was my problem. The strangest symptom was that it would heat up (above the temp where the clutch should engage) on a long climb (full load) when the outside air was cool (50s) and I was traveling fast. The fan clutch MUST engage even in that situation to assure that sufficient air passes through the radiator. I was thinking that the fan was only needed when you weren't moving, but not on these diesels.

Also, if you have a sec, would you check out my thread about my ALDA?

'87 300TD poor performance returns

I would appreciate your opinion. Thanks,

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-Mike
'87 300TD 304kmi (RIP)
'95 Toyota Camry Wagon 125kmi

The 87 300tdt that I bought with the engine disassembled had been diagnosed by the dealer as having a cracked head due to over heating. The PO had the trap oxidizer removed after the overheating problems began, and as one would expect, the overheating continued. New radiator, water pump,
thermostat, hoses followed, with no change in the overheating. The car was finally towed to the dealer, who declared after taking things apart that the head was "bad". I bought the car at that point and installed a good engine from a yard that incidentally still had the trap oxidizer on it. Recently I took the original #14 head to a machine shop to have it checked out and lo and behold I'm told that it is flat and not cracked! So somebody missed something,
probably a bad head gasket NOT a bad head. I wonder how many heads have been replaced due to misdiagnosis, thus giving the lowly #14 head its undeserved bad name. From reading this post it seems many more of the original heads are doing just fine, given that some other problem hasn't toasted them.
Steve

We have three 1987 300D's in our stable, and none show any signs of head cracking.

I can't quite fill out your survey. Yes, my head shows signs of cracking, but it has not failed. I've driven it for ~40k with small hairline fissures that allow combustion gases to enter the coolant, but do not allow coolant to migrate out. Driving on borrowed time I guess.

!987 300D, 187K miles, still going strong, no overheating.
Ted

Uh - that *is* a cracked head, Casey, lol! It's just in the early stages of cracking, that's all. Might wanna fix that before intercooling and pumping up the beast!

It's all part of my perverse master plan Dave. There's a madness to my method, but I'm not at liberty to discuss these plans yet

I had the Trap replaced at 155K, immediatly after I purchased the car.
The car usually runs at about 80 degrees C, except in summer traffic with the A/C on, when it has run close to the 100 mark, but has not reached or passed it.

Bill Ciocco
Mt. Pleasant, SC
1987 300DT

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Bill <><

Have not been able to find much info on the #15 head, I think it is original and may have been a running change on the 1987 300TD, although I saw one post saying they did not think a #15 casting existed.

No signs of cold colant pressure as of yet. Trap oxidizer has been replaced but not sure when.

~202K 1987 300TD

The six casting numbers are 14, 15, 17, 18, 20, and 22. Most - possibly all - cars imported to the USA in 1986 and 87 have the 14 head. From 1990-95, they came with the 17 head. If you bought a new head after roughy 2000, it will be a 22 head. The other three casting numbers (15, 18, 20) are very rare and so far I have only heard of ONE of each in the USA!!

87-124.133--Head failed at 103K prior to removal of the trap circa 1997. I installed a used head from a 126 car, fully reconditioned by HeadWerks in Bloomington MN. (this shop would make a semiconductor clean room look dirty) Prior to and after replacement I still had "running hot"(100°c+) issues until Mercedes replaced the entire exhaust system. The repair consisted of replacing the trap with a bypass, as well as installing a new generation soot reduction device ahead of the first muffler, this in about 1998. Now at 185K, the car has continued to perform perfectly my only gripe being it doesn't run near as warm as it did prior to the trap removal, but in the summer with the air on at sustain 70+ mph speeds, I'm pushing the 100°c mark on the temp gauge. Neither my 128.201, or my 124.131 car have ever run above the 85°c mark, ever no matter the load.

I really believe the head design is just fine, I think think the trap oxidizer was the problem, as I have heard of virtually no failures in the 602s, or 606s, just the 603s from 86-87, as witnessed, the 603.970 in the 126 and 140 cars never had this problem, similar head design, no trap.
-Mark

My head cracked at 160k, my wife was on a trip and probably was not paying the least bit of attention until black smoke started pouring out! The car is parked now until I get some time with my father in law. I hope it is just the head. Either way I plan on fixing the car as my extra.

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1987 300 SDL
Working on the engine!
It's up and running!

I was warned about the head when I bought the car and I have replaced the radiator, upper and lower hoses, aux water pump, and I was told the thermostat is new. I figure I have a little while before it goes because of the low miles 168k

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Owen

87 300TD 603 I-6
94 Jeep XJ I-6 4.0 (see the pattern)
89 750il
seventy-two hundred feet above sea level (kinda cold up here)

254k on the original 14 head and probably the orignal head gasket. I am not worried a bit, my cooling system is perfect. I'll blast the AC in traffic with the temps north of 100 and think nothing of it, the temp never climbs much over 90C.

Besides even if it does crack so what? Any car can blow the head I'll just drive the SD for awhile as I find a used one and send it to Metric motors for reconditioning.

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1999 SL500
1969 280SE
2023 Ram 1500
2007 Tiara 3200

What are the symptoms of a cracked head? It sounds that these cars will still run even with a cracked head. Ziet says there's gasses getting into the coolant, how do you know that? If that were the case I would imagine the plastic coolant tank would blow from the pressure or I guess the cap would let the excess pressure escape. I know there was a thread about about this earlier but it's long and I don't have time to go through it or find it at this time.

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DJ


84 300D Turbodiesel 190K with 4 speed manual sold in 03/2012