New 250D owner with lots of queries!

[MB250D]

Hello everyone, apologies for my first post being one full of questions!

I've just bought a shabby 1987 250D. My first Benz, AND my first diesel!

I'll try and keep it short, and hopefully someone can help!

1) My fuel gauge reads wrongly - when it reads "1/4 full", the tank is empty, as I found out last night! Does this suggest a fuel sender problem in the tank, perhaps? And if so, could some kind soul tell me where to find this sender?

2)Opposite my temp gauge, I have an oil gauge - marked from 0-3. Is this an oil level, or oil pressure gauge? Mine is pegged out at "3" all the time, even with the ignition off - does this suggest a sender problem, or maybe just a sticky needle? Where would I find the sender for the gauge, if anyone would know?

3) Oil capacity! I want to flush out the engine with some cheap oil for a couple of hundred miles before I put anything decent in it. How much will I need to buy, and what grade would you folks reccomend (for the good oil)? 15w40?

Apologies for all the questions in my very first post - but I have no owners manual, and haven't had a chance to buy a workshop manual yet! (Only bought the car last night).

Many, many thanks in advance for any help!

Cheers,

Patrick

 

[Shude]

moving to the engine section...

 

[andy_k]

First of all welcome

you can get the owners manual from your dealers
and Haynes do a workshop manual (No 3253)

yes it sounds like you have a faulty fuel sender and oil pressure guage - it should drop to zero when the engine is switched off and I'd expect it to drop slightly below 3 at tickover - as long as it rises to 3 as soon as you apply the throttle then pressure is fine.

The fuel sender is in the boot under all the trim and shouldn't be too hard to get at and the oil pressure sender is usually on the side of the engine - I'm not sure where it is on the diesels


There is always a possibility the dashboard unit has a fault - for two guages in the same area to be malfunctioning would certainly arouse my suspicion. Depending where you are you may want to get an auto electrician look at it for you or a local Merc specialist who may have a spare dash unit to check it against
HTH

Andy

 

[Sp!ke]

Welcome to the forum Patrick :bannana:

1) Common problem - most likely sender in tank. (approx £70 for part) Some people have successfully cleaned them.

2) This is pressure sensor. Should read close to 3 at anything over tickover. Sounds like sensor failure or you got some real thick old oil in there...


3) 5 litres should do it for a simple oil change - if you change the filter too, I think you might need a wee bit more. 10w 40 is what I use personally. Most specialists will recommend using a mineral oil or semi synthetic (not fully) on MB's of your vintage.

 

[Robby]

Instead of flushing it with crap oil, I'd just run through a tin of engine flush, change the oil, and put in a decent semi syn or fully syn.

The fuel senders are a known weakness on the 190s - on my old 190E 2.6 it didn't ever read fully full, even with a brimmed tank. I assume the top of the sender had rusted from the tank sitting half empty for ages and wasn't doing its thing.

Do the oil change before doing anything to the oil pressure switch, my pressure sensor was reading a little low until I changed the oil.

 

[Ian B Walker]

welcome mate. Oil pressure problem is definitley the oil pressure switch located ( looking at the engine from the front of the car) on the rear right hand side of the engine just below the Oil Filter. Its dead easy to change and a new one costs £28 +vat from the stealers. I use Millers XSS semi synth oil and would reccomend it to anyone, you will need 7 ltrs. (they also do a diesel version)

 

[MB250D]

Great advice all, thanks! When I say flushing it with crap oil, I actually have a bit of a recipe I use to flush engines - I put a tin of flush in with the old oil, drain it after 15 mins, change the filter, then fill up with cheap oil and a litre of ATF (Autobox fluid). It's really high in detergents, and cleans the engine out nice and gently (but very thoroughly!) over a week or 300 miles........ I had an old 535i E34 BMW which was a black sludgy mess inside, after a couple of changes with cheap oil and ATF it looked like new under the rocker cover, and ran like a dream......
As far as the oil pressure gauge goes, I'm starting to think it could be a sticky needle - surely it should read zero with the ignition off, otherwise? Even when I get in the car from cold, no key in the ignition, it is sitting at 3 bar, which makes me think (presuming it is an electric gauge?) that it may well just be stuck there? Glad to hear it's a pressure gauge though - I hate driving a car without one, the "Idiot light of engine death" is the worst thing to see!
The fuel sender - would anyone know what sort of form this takes? I've been driving, fixing, crashing etc. VW's for 10 years now, and the sender on those is a simple float on a wire arm, which in turn moves a contact up and down a carbon track to give a signal to the gauge - are the MB ones much different? £70 for a replacement is a bit much - I only paid twice that for the car (with MoT and new tyres!). Would be very interested to hear about cleaning/repair.......
With regards to the oil, I think once it's flushed properly I'll use VW oil - not sure if it's popular among MB people, but the Quantum Silver oil (10w40 semi) is the best I have ever used. About £13 a gallon from GSF, a couple of quid more from VW themselves. Because the VW engines have famous problems with valve stem seals, it contains a good amount of seal improver (sweller), and is pretty much the best oil around IMO - I have used it on all my cars and it really is great stuff. I'll stay away from fully synth - had problems in the past with 5w30 running past seals which had previously been fine, and I'm not really willing to fork out for the Mobil 15/60 fully synth!
By the way, if you ever need advice on VW petrol engines, feel free to ask/mail me - I've had 17 Mk2 Golfs, and a couple of Passats, and I know my way around (and inside!) those engines as well as I'm sure you folks do your MB engines!
Many thanks to those who have replied so far, and the kindly mod who moved my thread to the correct section - and thanks for the warm welcome!

Cheers,

Patrick

 

[MB250D]

welcome mate. Oil pressure problem is definitley the oil pressure switch located ( looking at the engine from the front of the car) on the rear right hand side of the engine just below the Oil Filter. Its dead easy to change and a new one costs £28 +vat from the stealers. I use Millers XSS semi synth oil and would reccomend it to anyone, you will need 7 ltrs. (they also do a diesel version)

Oh! Would that make the gauge read max pressure, even when the engine and ignition are off?

 

[Ian B Walker]

Oh! Would that make the gauge read max pressure, even when the engine and ignition are off?

alas, yes it would Partick. It is quite common. Happened to most of mine at some stage.

 

[MB250D]

Excellent stuff! I don't suppose you would know if the sender is available from GSF or ECP, would you? Knowing my luck it'll be a dealer part only.......
I can just see the conversation
"Hello, would you have an oil pressure sender for a 1987 250D?"
"Not until you move that heap of junk out of the car park - go and put it in the B&Q car park across the road, or something........ it's driving away the customers....."
:-D

Thanks Ian and all, any more info about cleaning the fuel sender would be most welcomed as well!

Cheers,

Patrick

 

[Dieselman]

Actually the dealers is probably the cheapest place to buy parts and don't worry about the age of the car, there are lots of old Benz at dealers.

 

[andy_k]

Actually the dealers is probably the cheapest place to buy parts and don't worry about the age of the car, there are lots of old Benz at dealers.

you'll also probably be very pleasntly surprised by the welcome and service you get

Most of us W124 owners seem to get treated better than the owners of the newer cars

Andy

 

[Tan]

Actually the dealers is probably the cheapest place to buy parts and don't worry about the age of the car, there are lots of old Benz at dealers.

Some of the dealers offer a discount on parts for older vehicles, so its worth asking.

 

[Dieselman]

you'll also probably be very pleasntly surprised by the welcome and service you get

Most of us W124 owners seem to get treated better than the owners of the newer cars

Andy

That's probably because you're not pompass ass****s that talk to the staff like they're a piece of dirt.

 

[Ian B Walker]

you'll also probably be very pleasntly surprised by the welcome and service you get

Most of us W124 owners seem to get treated better than the owners of the newer cars

Andy

Its been well documented here by me and others but Mb Blackpool rock. I always seem to be treated as a) an adult. b) a potential new car customer. c) with dignaty and respect d) nothing ever seems to be too much trouble and lastly and most importantly With HONESTY

 

[andy_k]

That's probably because you're not pompass ass****s that talk to the staff like they're a piece of dirt.

aha - that explains it

I'll give MB Eastbourne a quick plug and say that the level and quality of service I receive from them far exceeds what I'd expect for what is basically an occasional parts customer (me).

Andy