Defender91

Defender91

Active Member
Hi,
Wondered if someone would be able to put my mind at ease.
I rebuilt the 200tdi in my defender around last Christmas, all bearings and bushes replaced and a new oil pump.
I've just got round to getting an oil pressure gauge that I know is reading correctly, but the figures don't match the manual.
At cold idle,it's around 4.6 bar which increases to 5 with any revs.
However,after a 30min run the pressure drops to 1 bar at idle increasing to about 2-3 with revs.
This didn't seem right with the manual saying between 1.7 and 3.4.
Is this something to be worried about ?
Thanks
 
1 bar at warm idle does sound a bit low, on the other hand 4.6 at cold idle sounds high, what oil are you using?
 
Just thinking, my Turbo is a bit tighter than it should be,so could it be that it is overheating the oil and thinning it?
Probably not but Its just something I thought of.
Thanks
 
Cannot see turbo being an issue.
Dont forget std def turbo has a fibreglass type heat shield which pretty much covers the turbo and some of the downpipe.

Cheap test has got to be drain the semi syn, and chuck some mineral oil in there, keep the syn as its still new.
Tdi and mineral oil go well together.
 
Thanks for the suggestions.
Not sure what you mean by the fibreglass heat shield, the castings on mine are open to the air.Sounds like I'm missing something.
Pretty sure I had mineral in there before, I got the semi synth as it was recommended.
I've also tried 10w40 and changed to 15w40 but it didn't seem to make a noticeable difference to the pressure.
I've heard the oil thermostat can cause oil pressure problems,do you think I should investigate this?
Thanks
 
As @lynall above, keep with 15w40 mineral + how many miles have you driven on the rebuilt engine? If engine rebuilt did you use running in oil for the first 100 miles...and then change to std 15w40?
 
Getting on for a 800 miles now.
I did use a running in oil to start with,then switched to 10w40.
However, wasn't till around when I changed to standard oil did I fit an oil pressure gauge,and that always read fine.Found out later that gauge was not reading properly though.
Sorry if this doesn't make much sense, it was only when I went for a drive of more than about 30mins did the pressure drop to 1 Bar so I went some time before noticing it.
I've now got a new matched gauge and sender and cross checked it with a known anologue gauge to take the gauge out of the question.
Thanks
 
Defender91 said:
Thanks for the suggestions.
Not sure what you mean by the fibreglass heat shield, the castings on mine are open to the air.Sounds like I'm missing something.
Pretty sure I had mineral in there before, I got the semi synth as it was recommended.
I've also tried 10w40 and changed to 15w40 but it didn't seem to make a noticeable difference to the pressure.
I've heard the oil thermostat can cause oil pressure problems,do you think I should investigate this?
Thanks
Click to expand...


There is a good post on the oil stat and filter head in the 200tdi engine section, Think Steve wrote it? Iirc one 0-ring gone hard can cause low oil pressure issues.

Heatshired was fitted as standard, sadly they are carp, the heat kills them and do not last, rare to see them still fitted.

Item 10

Screen Shot 2020-05-12 at 19.48.18.png
 
I got the cylinders honed,new mains and big ends,cam bearing replaced and bored and rebuilt my oil pump with turner gears and release plunger.
I see what you mean by the fibreglass shield, mine had the bracket but it never had anything attached to it.
I'll check out the thermostat post on the oil stat,thanks,one of the few things I didn't end up replacing when I did the engine.
 
Just checked the oil thermostat this morning,started opening at 70.c,fully by 90 so that's fine.
Had a single washer in there along with the spring.
 
Just been out for another run, the pressure started out as normal at 4.5- 5 bar.
After 30mins, the pressure was at 1 bar at idle,but even with revs wouldn't go beyond 2.5 bar.
I haven't got a oil temperature gauge,but a heat gun pointed at the various oil lines were all around 75.c,so no problem with the oil overheating.
Has anyone got any suggestions on what could be wrong, I'm willing to try anything as this is getting quite frustrating now.
Thanks for any replies.
 
Thanks for replying
Ive ordered some ,but the post is being slow so not sure when it'll arrive.
Just looking for anything else that could be causing the problem before I have to go back to work.
Thanks
 
Watch the oil level, I tried a 300tdi on syn oil many moons ago, and it drank it! back to mineral and the oil consumption stopped overnight.

Mate had a 200 that ran low oil pressure, in the end we popped the cam side plates off, and one of the shells had shifted.
This was mainly when it got to normal temp, and from his house was about 4 miles of motorway work.
We did try a oil pressure gauge, but I cnanot remember the readings, but they were so low the oil light was coming on.

Years ago we had a few trucks where the oil light would flicker at hot idle, they ran for years like this.
 
It never drinks a drop of oil, prefers to leak it all over the drive.
Had the cam bearings changed when I did the engine so hoping it isn't them. Would have thought it has be related to either temperature and the oil viscosity otherwise I'd never get the 4.5 bar at idle.
It might have had this problem for a while,as I stripped the engine after my oil light stayed on for about 10 seconds on startup. Unfortunately I didn't have a gauge at that point.
Couldn't be that the gauge is reading wrong when in hot oil?
 
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