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took my 300dt into the mechanic for a valve adjustment and with that a new valve cover gasket, had waste gate hoses replaced, and vacuum valve replaced. also new over flow hose. the loss of power on any kind of hill is now worse than before, it feels like you are dragging an anchor behind you. Was driving thru the Caldecot Tunnel and while i was driving thru Orinda/Moraga up the 24 I was at 35mph with constant pressure on the gas peddle. Question, does each cylinder have a fuel injector or is there only one? And, do you think that if I replace the injector should I also replace the injector pump?
Why don't you take the car over to European Auto Repair in San Rafael---they know what they are doing. You can't be replacing things like an injection pump without really diagnosing things, that's way too expensive for "guessing".
There are speciality shops that can fit you with a hitch I think. You should try your local Yellow Pages.
Maybe you could rig up a cold air intake, use synthetic oil, inflate your tires, adjust the valves and time the injection pump---that might give you a little boost and better throttle response.
I also think the timing is off. My mechanic tells me it to much trouble with a car that has Sever Blow By. And that I need a new engine. :shades:
Injection pump timing doesn't "go off" very easily, so I'm dubious about that diagnostic. Only a real expert should ever attempt injection pump timing.
I recently bought a 1978 mercedes 300D with 80,000 miles. When I am driving on the highway for a while and then get into stop and go traffic my oil pressure drops down. Most of the time my oil pressure guage reads at the top, 45 lbs per sq in. When it is problematic it will drop down to around 20. The pressure only drops when the car is stopped and in gear. I have been dropping it into nuetral and that has seemed the take some of the load off of the engine.
One other sign of oil pressure issues is the the air filter has oil that has been pushed up into the filter housing. It drives extremely well and has no problems. Is there anything that I can/should do to help this old mercedes along?
thanks
jonathan
As for oil in the air filter housing, you just have to keep that clean. Old diesel engines are kind of dirty nasty things or SEEM to be--ever notice that your engine oil is dirty ten minutes after you've changed it?
New diesels are way more sanitary.
Again, just wipe out the housing and keep those air filters fresh in there by rotating them away from the oil scum. I used to change my oil every 3,000 miles and the air filters once a year regardless.
Diesels have no ingition so the only way to shut them off is to shut off the fuel. Benz does this by engine vacuum....so, vacuum loss = engine stays running.
Replacing the vacuum shut off switch may or may not cure your problem, depending on whether the switch itself was causing the vacuum leak or was merely affected by the vacuum leak.
If that doesn't do it, then you have to go on a "hunt" for the vacuum leak.
If it does, then I would suggest that the first thing you need to do is probably replace your glow plugs if this hasn't been done in the last two years.
And you'd better be careful with starter fluid in a diesel.
If it won't start even with starter fluid you might want to have a compression test done to see where the engine is at.
Also, since this is a compression start engine, if any one cylinder is low on compression, this makes starting very tough.
I think you know what happened.
I have heard of the oil pan being blown off a motor but never verified that. But if you had a whole can of that stuff in the crankcase along with lots of raw gas and then you managed to find a spark....well......
Don't know if that could happen to a diesel....kinda doubt it, but you could wash the cylinders dry of oil. Ether is an amazing solvent.
I removed the fuel filters and found black fuel/water in the secondary. Replaced both filters and put injector cleaner in the secondary - no real improvement.
I removed and replaced the air cleaner - it was clogged and had a heavy oil deposit. Investigated further - there was some blow by - but no real oil burning - no oil needed between changes.
I loosened one injector feed at a time - looking for a non running cylinder. All five cylinders showed the same decrease in speed and roughness when loosened - and all recovered fine when tightened.
Ran thru the tank of fuel - topped off the tank - and removed the secondary fuel filter - black again. Drained it, topped it off with injector cleaner - and there is a bit less smoke - but still more than before.
Questions?
1. What do I look for now?
2. The transmission seems to shift up sooner than it used to - is the vacuum part of the shift controller? Our doors stopped working years ago and I suspect we have many vacuum leaks but don't know where to start to fix them. The breaks work fine so I feel the vacuum pump is working.
Thanks - clearly it makes no sense to put a lot of $$$ into the car - but I suspect this is something simple.
I don't know what to say about the filters but you may have a grunged up fuel tank if you haven't been using some kind of bio-cide regularly. All kinds of crap can grow in diesel fuel tanks and you need to kill it off...it's like algae, amazingly enough.
You may need to take a large fuel sample to see what you are pumping into that engine.
Those are my most basic of concerns. Thanks!
mateo
As for rust, well if you aren't concerned, that's okay but keep in mind that this car would have to be pretty cheap if it has rust on it.
Can rust be repaired? Is it worth it? By the way, thanks so much for answering those questions.
$750 sounds about right, that's what I was going to suggest actually.
It's hard to say really since the transmissions in that car are kind of goofy, as compared to the way American transmissions feel, and shift.
And yes, there should be a kickdown switch, although it's pretty lazy. I always tell people to shift these cars manually up and down, since they are so grossly underpowered. You need to stretch the revs in each gear if nothing else for your own personal safety and to prevent a Range Rover from running over you from behind.
the car is running well considering its 350k in 20 years on the road. engine's ok, (valves sometimes make that noise which is silenced as engine reaches the optimal temp). The automatic transmission works ok, had a problem with the a bursting pressure tube connected to the radiator but fixed it without serious damage. Sometimes when i charge (overcoming or hill) i see a blue fume in the back. well this might be quite usual for a 6-cylinder 3.0 L but concerned if that is caused by an engine power loss or oil consumption from worn piston rings or the fuel quality.
hail to the mercedes craftsmanship!
So I'd just shop for a 300D if that's what you want. Fuel mileage will be about 20 mpg city and up to about 26 mpg highway. Performance will be better than a 240D but nothing like a turbo-diesel. Comfortable cruising speed is about 70-75 mph and yes, you will still slow down going up hills. At high altitude, you'll have to get out and push. You only have maybe 85 HP there in a heavy car, so....
If you want to turn three junkers into to one good car do it as a hobby not as a means of day to day driving. Look for a 300D in good condition, they're out there.
My daughter had a 77 240D that I feel was a clone to my 79 300D. Ran like a top (on flat pavement) but would not get out of its own way. Both had Auto trans that required nothing but filter and fluid changes. The 77 240D was junked after 280K miles because the body and frame was rusted beyond safe operation.
Good luck.
thanks
Please give a litle more info about what component you changed. The main components are the pushbutton assembly on the dash, the Climate control servo under the hood (controls vacuum and hot water flow), and the fan controls.
Once the car cools down, you should be able to run it and see if water is circulating in the radiator AFTER the thermostat has opened. Your thermostat could be stuck, too.
Overheating is a lot harder to diagnose than people thing. There are multiple causes:
coolant leak
clogged radiator
stuck thermostat
blown head gasket
cracked cylinder head (exhaust gases leaking into water jacket)
broken impeller in water pump
broken fan belt
broken electric cooling fan
bad sensors for cooling fan
crude in engine block
excessively lean fuel mixture
air blockage in cooling system
transmission cooler and radiator exchanging fluids through damaged tank
collapsing water hoses