My 1978 300SD Turbodiesel had a power loss after a "fast" highway ride uphill.
The temperature went little higher than normally but stayed at the 100 C mark.
I checked the coolant and the expansion tank was empty. Also some oil was dripping in the driveway.

Now it takes forever to even accelarte to 40mph.

I cleaned the ALDA system but no improvement.

Now I'm thinking that the cylinder head gasket might be shot.

Any suggestions?

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'80 300 SD, 300k

Change BOTH fuel filters first and see if that helps. Top up the coolant and check the oil and try it again. I think it is too early to condemn the head gasket yet

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2012 Mercedes ML350 Bluetec 91K (hers)
2005 Corvette 55K (fun car)
2002 VW Jetta TDI 231K (mine)
1998 Volvo S70 T5 Turbo 196K (kids)
1994 Ford F150 4WD 249K (firewood hauler)
1983 Mercedes 300D 376K (diesel commuter)

Way too early to diagnose headgasket. I concur--fuel delivery problem. Swap out filters and if that doesn't solve the problem, swap out inlet and return lines under the hood to test the tank screen. If problem solves with tlines swapped, tank screen needs to be cleaned. Could also be a linkage problem in the accelerator. Or a failure of the vacuum in the shut off valve to completely bleed out.

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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

Also make sure you're not building vacuum in the tank due to a clogged tank vent. After driving pull the fuel cap off. If you get a big suction noise then the tank vent is clogged.

With the coolant issue. I'd check on your water pump. It might be leaking. also check and tighten all your hose clamps. and check the condition of all the hoses in the coolant and heater system.

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Ok -
1. changed both fuel filters: no improvement.
2. checked the fuel tank: no vacuum (ventilation is good)
3. refilled the coolant - no further coolant loss

However - blow by shows lost of smoke coming out. Accelation ok until 25mph but then very slow - didn't push it beyond 40mph

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'80 300 SD, 300k

Did you check the linkage?
Swap th einlet and return lines.

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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

yes - also checked the linkage - looks ok.

I didn't switch the lines yet

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'80 300 SD, 300k

Are you running diesel or an alternate fuel ?

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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

Diesel

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'80 300 SD, 300k

I would say next step is to swap the inlet and return fuel lines in the engine bay and see if the tank screen is clogged. Make sure you do this with no less than 3/4 of a tank of fuel though.

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2012 Mercedes ML350 Bluetec 91K (hers)
2005 Corvette 55K (fun car)
2002 VW Jetta TDI 231K (mine)
1998 Volvo S70 T5 Turbo 196K (kids)
1994 Ford F150 4WD 249K (firewood hauler)
1983 Mercedes 300D 376K (diesel commuter)

Tonight a friend of mine came by: diagnosis the turbo doesn't work!
We found a chip in the fan.
The probable reason for this: the air filter case broke and probably one little metal piece went into the turbo fan (the airfilter was still connected through the other 2 remaining screws).

Why did the air filter case brake? Probable reason: didn't use washer and didn't use original screws.. I bought them at Loews...

Now everything is disassembled - I had an other turbo fan from a w126 in my garage which we cleaned. Tomorrow we'll assemble everything and then let's see if that's the solution for the power loss.

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'80 300 SD, 300k

I believe that some turbo compressors appear to have a chip in the blade. Once you make the swap out you will know if a change has been made. Did you check for boost? (using a gauge).

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83 300TD (need rear wiper assembly dead or alive)
84 300SD Daily driver
85 300TD almost 400k miles and driven daily.
98 E300D *sold
86 300SDL *sold and made flawless 10 hour journey to new home.

Check fuel pressure

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Current fleet
2006 E320 CDI
1992 300D - 5speed manual swapped

former members
1984 300D "Blues Mobile"

1978 300CD "El Toro"

long story short: the turbo was broken - some blades were bent (which seems to be normal) but some didn't look correct (some little parts missing). The main thing is that the fan was really hard to turn manually. Probably the bearings are not good.

At the end of the day: the "new" turbo from the w126 works very well (has also some bent blades and some blade pieces missing but it turns very well - so the bearings seem to be ok)

thnx

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'80 300 SD, 300k

Ding ding. Problem found.

Glad you got it figured out.

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83 300TD (need rear wiper assembly dead or alive)
84 300SD Daily driver
85 300TD almost 400k miles and driven daily.
98 E300D *sold
86 300SDL *sold and made flawless 10 hour journey to new home.