Low compression mk1 golf diesel.

:dontknow: Hi everyone. I'm new to the forum and I've just aquired my first mk 1 golf. It's a 79 1.4 L diesel. It looks scabby but it's rock solid. However, I have an engine problem that I need some advice about. It won't start on the key. But it will tow start. I've done a compression test and two of the cylinders are showing a bit low. I decided to change the oil as it looked a bit loppy on the dipstick and found that it wouldn't drain. The oil was thicker than treacle. Two engine flushes later and a gallon of cheap oil flushed though and it was all clear. But it hasn't made any difference to the running. I think that maybe the piston rings are gobbed up with sludge and thats what's affecting the compression. Does anyone know of any stuff you can get to free off my sticky rings?

 ops: Er, sorry about the username. I'll change it asap.

When you find something that really works, let me know!

Firstly do a compression test -with the correct guage for diesel not petrol or you will blow it up -dry then wet this will determine if its rings / bore wear or valve trouble . Cylinders should be within 15% of each other , tell me what you get .#

If the car will not start on the key ripout and test all your glow plugs , have you got power to them all ? They should "glow red hot on test" if in any doubt replace them as they are quite cheap .

How old is the fuel is it fresh and is the diesel filter new ? Have you any water in it ?

Whip out the injectors do the compression test then fill the bores with a good dose of Redex while you check the rest . This will help loosen all the crud if any  


Post your findings Cheers ……

:dontknow: I had a guy look at it when I bought it. He tested the glow plugs and said they were all o.k.  He did a compression test and told me that two of the cylinders had low compression. I think he said the 2 that were low were showing 40 psi. Apparently, this is why it won't start on the key. He said that a starter motor won't turn the engine over fast enough to get it going with only 2 good cylinders cause it's a diesel. That's why it will only start by bumping it off. It turns the engine over a lot faster than the starter ever could. Trouble is this is my first diesel so it's all a bit new to me. Oh, and i've even tried squirting easy start down the inlet manifold to get it going, with no joy, but I did notice there was a bit of oil in the air filter box. The fuel is fresh as it was totally empty when I bought it. Although I've not changed the diesel filter yet, I have made sure that diesel is getting through and it smell o.k.  I can't believe I'm having this much trouble with it. Believe it or not it is a genuine 40,000 mile car, and has only had 2 owners from new. The previous owner was an old boy who has had it for 20 years. Trouble is he was one of those do it yourself types that, unfortunatly has got no diy skills what so ever. He even repainted it himself….. with a tin of signal red dulux, and it looks like he used the shaggy dog off those adds to apply it as well! He's been retired from driving for the last 5 years and it has just sat in the garage without being turned over regularly. I've been thinking about dropping an engine in from another car, but VW 1400 diesels are as rare as hens teeth. In fact mk1 golf diesels are pretty rare now. Do you know if the 1.6 diesel out of the mk2 golf would go in? If it would I could get an engine and box complete from a scrappers and gain a fifth gear in the process.

Compression is all on a Diesel. A petrol with very poor compression will start and run quite easily if the rest of system (fuel and sparks) are OK. It might pull very poorly and smoke etc but should start as petrol is very  8O very 8O  very  8O explosive.

You?ll understand your problem with low compression if you consider how a Diesel works. It compresses the air it?s just drawn in to 23 times atmospheric pressure and in doing so raises the temp inside the cylinder to 800+c so that when the diesel is squirted in it immediately burns and pushes the piston back down. No compression, no heat, no burn and an engine that fails to start or run.  :cry: In addition to the compression the timing has to spot on, again a petrol will still start and run with the timing miles out (again might run like a bag of spanners but will still run) Diesels have to be spot-on.

The above assumes that you have tried all the obvious tricks like cracking open the joints to the injectors and making sure diesel is evident when the starter is spinning it over. :dontknow: Also do you have the coldstart thingy pulled out?

Most starting problems on old indirect injection engines can be traced to duff glow plus, are you sure yours are OK? I must admit a dose of 'sniff' usually got completely knackered tractors going when I lived down on the farm.

1600D engines are always coming up on Ebay usually from Caddys. They are now all at least 13 years old and are being scrapped with rotten bodies but engines can be OK.

Look on www.vwcaddyforum.com , there are a few very knowledgeable diesel types on there and www.vwdiesel.net has complete sections devoted to the IDI engines, although it very US/Canada based. They have solutions to starting Diesel Golfs at -40c!!!!!

your clue is in the oil in the air filter , the compressions are blowing back past the rings because they are worn and pressurising the sump forcing oil in to the filter . I have seen Golf MK1 diesels run them selfs to death by starting to burn the sump oil via the filter until there is no oil , later cars had a different breather system to stop this .

If it was me !! I would rebuild the engine , spares are quite cheap , rings ?40.00 a set etc .

Its not uncommon for the Diesel Golf of this age to have a worn engine , the oil change interval for the MK1 was 4500 miles and if this was not carried out they rapidly wore out .

The later engine from a Mk2 will fit it uses the same block but try to find a good one , like the preverbial rocking horse ….

Yeah… I have the same problem with my Mk1 diesel, but not as bad as yours. Mine is a two-owner car (oh how I hate the term "keepers"!), both of whom were elderly for at least part of their ownership, and both of whom only drove the car locally. So here I am with a dead straight, tight as new, 158,000km, almost immaculate car with low compression because of short trips failing to get the engine up to proper operating temp. Here in Tassie people don't drive far. I came from Western Australia where you drove 50km to get the morning paper, but here a drive to the corner shop is regarded a an epic voyage! The former owners got the car "serviced" at the local garage, which during the 80s and early 90s probably hadn't seen a diesel car before. I have the service history, and apart from the first service, which had to be done in Launceston, 150km away, all were done locally (but on schedule). So I am commited to rebuilding the engine. Apart form new big end cap bolts I have everything to do it (although I would dearly like to get my hands on a dial indicator to do the timing!) and when my leg's out of plaster I will probably get around to it. At present as winter hasn't set in, it's starting first go. I replaced slow glow plugs and relay with fast ones (ebay US) and put in a 630CCA battery which spins it over real fast. Stripping the engine is not difficult. Sump drops off and apart from the timing belt removal and replacement the head is straightforward.
As far as your engine is concerned, the compression on the two crook cylynders is very low. It could be that the problem is stuck rings. I like the Redex idea, but you will need to pour it into the injector holes and leave it for a couple of days. Even then, it may not get down to the second ring. Don't forget to replace the heat shields!
Good luck!