Hello, does anyone have an answer to the following? Help is greatly appreciated. 84 300d.

Car overheated just bellow the red on the gauge. Pulled over immediately and let it cool and some bubbles showed and percolated in the coolant overflow tank.

After cooling, drove the car 160 miles and the temp never made it over 90. Was about an 1/8 of an in below 90 before the over heat, now the needle barely touches the bottom of the 90 line.

There has been a knock since then from the middle of the head. Its been 2 weeks and no over heating and temp never above the 90 mark. I thought the knock may have been the injectors so I rebuilt them, pump tested them, installed and the knock remains. Before that I thought it could be valves, they are set with near perfect gaps.

Finally, I have tiny amount of white smoke at start up, engine temp warms up a little faster (but the weather temp has increased too), no knock until the engine runs for a minute, and no consumption of coolant. And I am not sure if there is a loss of power because I may just be being paranoid about the power. Climbs to 75mph very easily.

Any help on this is greatly appreciated. I cannot stand the sound. If it's the head I'll take them in, resurface them and reinstall assuming they are not cracked or unless there are other recommendations.

Have done:
-Fuel injectors,
-Valves are have perfect gaps.
-All front and rear bushings and mount and checked their "tightness."
-Torque converter bolts are good.
-Recently replaced the exhaust, intake gasket.
-Replaced my exhaust system 1 month ago.

Again, thanks for any help.

how many miles has it done? Is there much blowby?
you may have had an air lock for some reason.
Can you get a better indication of the location of the knock in the motor. top end? front or back?

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Grumpy Old Diesel Owners Club group

I no longer question authority, I annoy authority. More effect, less effort....

1967 230-6 auto parts car. rust bucket.
1980 300D now parts car 800k miles
1984 300D 500k miles
1987 250td 160k miles English import
2001 jeep turbo diesel 130k miles
1998 jeep tdi ~ followed me home. Needs a turbo.
1968 Ford F750 truck. 6-354 diesel conversion.
Other toys ~J.D.,Cat & GM ~ mainly earth moving

Mileage - 145,000
Blowby - a medium to high amount
Knock, center of head, slightly more predominant toward the intake side

air lock? is that a bubble in the cooling system?

If the knock developed simultaneously with the overheat event, and the injector is ruled out, you don't have much choice except to pull the head at this point.

I would be curious to isolate the problem to a specific cylinder prior to pulling the head. While the engine is running, crack each injector line............one at a time...........and see if you can find the cylinder that changes or eliminates the knock. This will allow you to target the problem when the head is removed.

Alternately, you could do a compression test and see if one of them is exceeding low...........however, your performance data with the butt-dyno may result in inconclusive results from this test.

The steam on startup is indicative of a coolant leak seeping into the cylinder on shutdown. Then when you start it up it turns into steam, hence the puff of white. It could be a gasket leak or a tiny crack in the head.

I think you can drive it that way for a while but you should plan to pull the head. If it gets too bad you could get enough to hydrolock that cylinder and bend a rod.

Good luck. Pray for a leaky head gasket.

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[SIGPIC] Diesel loving autocrossing grandpa Architect. 08 Dodge 3/4 ton with Cummins & six speed; I have had about 35 benzes. I have a 39 Studebaker Coupe Express pickup in which I have had installed a 617 turbo and a five speed manual.[SIGPIC]

..I also have a 427 Cobra replica with an aluminum chassis.

I hope it is the head gasket.

and, sound is not effected by injector/line removal.

white smoke, may also just be smoke. cannot tell if it is gray or white. there is hardly any

will do compression first.

Unfortunately, this result is undesirable. It's not related to a combustion event.

I cannot fathom any mechanical problem that results in a significant noise as described, that would be caused by a blown head gasket if combustion is eliminated from the equation.

Removal of the head will tell the tale...........and it won't be pretty.

I too am stumped by the knocking sound.

__________________
[SIGPIC] Diesel loving autocrossing grandpa Architect. 08 Dodge 3/4 ton with Cummins & six speed; I have had about 35 benzes. I have a 39 Studebaker Coupe Express pickup in which I have had installed a 617 turbo and a five speed manual.[SIGPIC]

..I also have a 427 Cobra replica with an aluminum chassis.

how's the vacuum?
it's very hard to isolate a knock on these motors. it may sound like it's on top center, but be coming from the flywheel or the vacuum pump.
of course it could be a bad rod...
when you start the motor cold, does the upper hose get hard very fast?
you could have more than one problem here.

Just a stab in the dark. I do not know the belt situation on your year and model, but I had a similar event regarding a "knock" I thought was coming from inside the engine. Turned out to be the belt tensioner shock. The bushing on the upper end of the shock looked good, but it wasn't, and was allowing the metal part of the shock to hit up against the engine, hence the knock. It was hard to pinpoint, but it was an easy fix. Hope yours is as simple a fix as mine was.

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96 E300d

A w123 does not have that set up.

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RRGrassi


70's Southern Pacific #5608 Fairmont A-4 MOW car

13 VW JSW 2.0 TDI 193K, Tuned with DPF and EGR Delete.

91 W124 300D Turbo replaced, Pressure W/G actuator installed. 210K

90 Dodge D250 5.9 Cummins/5 speed. 400K

How about air cleaner mounts?

__________________
1985 300SD
1998 Jetta TDI
Previous: lots of diesel VW's, MB's, KW's, Pete, Freightliner


Walking isn't a lost art: one must, by some means, get to the garage.

You can get a test kit (actually auto parts stores loan them out), which test for combustion gases in the coolant. When the headgasket went on my Landcruiser I could smell gasoline in the coolant overflow tank. I wouldn't pull the head without further confirmation of a bad headgasket using something like this test kit.

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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

I always wondered if they over heat too much what happens to the vale seals?

also can you get a us a video clip of the sounds or recording? does the sound get louder with engine rpm or does it get muffled when the engine revs? oh one more thing....does it go away at random or change sound at any point?

__________________
Wie lange wird Ihr Auto leben?

Under the red mark on the gauge is not really overheating, just really hot. Overheating is running it in the red for several minutes.

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-diesel is not just a fuel, its a way of life-
'15 GLK250 Bluetec 118k - mine - (OC-123,800)
'17 Metris(VITO!) - 37k - wifes (OC-41k)
'09 Sprinter 3500 Winnebago View - 62k (OC - 67k)
'13 ML350 Bluetec - 95k - dad's (OC-98k)
'01 SL500 - 103k(km) - dad's (OC-110,000km)
'16 E400 4matic Sedan - 148k - Brothers (OC-155k)