300Tdi oil pressure and temperature HELP!

disco baboon

Member
Oct 1, 2014
9
0
lingewaal holland
Last year , when I came off the highway the oil pressure light of my 300Tdi D1 came on. So I bought a gauge, hoping for the switch to be faulty: it quickly showed me the switch was just fine... :( so, next step:

Change the oil for a 20W50 and put a new filter in. that cured the situation for a while. Pressure was round 1,1 bar on idle when hot. Acceptable, but not according to RAVE specs.

Soon though, the light came on again. forcing me to the next step:
Changed main and conrod bearings, put a new oil pump in, said a stupid prayer, took a test drive with the oil light coming on at the end of it..

So, I thought: what if the pressure relief valve somehow gets stuck in open position when hot?? So I replaced the relief valve spring with a solid piece of metal . ..

>>>>>>> NEVER DO THIS !!!:

I pulled out of the driveway, revved it up to around 1700RPM and a Loud bang followed by an oil trail behind me...
Turned out that the oil filter gasket was (luckily) blown out by the high oil pressure, and that the pressure relief valve is there for a reason and working harder than one would expect :D

Back to the shed...

Took the engine apart and all I could find was a little-worn first cam bearing. Being fed up as I was I decided it was time for action, and bought a reconditioned engine from Turner Engineering, setting me back 3600 euro's.
I replaced the Turbo, the intercooler, ripped the aircon out, put a HD clutch in, changed everything I came across that looked a little worn, had my injectors serviced and mounted the bigass aircon fans on a newly made frame directly in front of the radiator. Two weeks later it rolled out of the shed again....

Took it for the first drive and after 27 km's .... THE OIL LIGHT CAME ON !!!!!!!!!!!!! :banghead:

Rolled back to the shed, got drunk, ordered a new after market radiator (the only thing not replaced so far) and put it in. Now everything seemed fine, although the engine wouldnt heat up. That was solved with a new thermostat, and it seemed I could finally start my break-in run for my newish engine.

Everything went well with the Turner supplied SAE 30 break-in oil, but I didn't go on the highway or above 2500RPM.

After 500mls I serviced it, and put in Full Synthetic 5W40 Valvoline oil. And after my first long run on the highway THE OIL LIGHT CAME ON AGAINnnnnn. So now I'm , apart from becoming mentally unstable, down to two options:

-The oil-thermostat is faulty, so the oil gets to hot, causing pressure drop (although I tested it in boiling water)
-The Chinese radiator has too much flow resistance in the oil cooler bit, and causes pressure drop (I noticed before putting it in that blowing air through the Chinese was a lot harder than the original LR one)

I'm now waiting for the Bearmach oil-thermostat to be delivered, and for any out-of-the-box ideas from you guys, because I've had it for now. Please send all Ideas , thanx,

Jasper from Holland
 

isavage

Well-known member
Jun 2, 2015
52
0
Augusta, Ga
Wow! Let me know what you find out. I have a gauge fitted to my 200tdi and sometimes when the oil gets hot the oil pressure at idle drops below 15 psi. If the oil temp thermostat fixes it I'd like to know.
 

disco baboon

Member
Oct 1, 2014
9
0
lingewaal holland
two updates: I fitted a new oil-thermostat and went for a drive: no change; oil light came on. And earlier I talked to a guy from a radiator recondition shop, and he told me he was almost sure it was poor radiator performance. So next step will be sending my old LR radiator to the reconditioning shop.
 

Tugela

Well-known member
May 21, 2007
4,754
562
Seattle
Rolled back to the shed, got drunk, ordered a new after market radiator

It sounds like you are doing things in the correct order. If replacing all other parts leaves you suspecting the radiator as the culprit, rebuilding your LR radiator sounds like a good plan. I looked into a similar option when I was replacing my own radiator and the shop said they could rebuild mine with aluminum components that were higher diameter/higher flow and would be more effective than the original. I don't know if the performance improvements extended to the transmission fluid and oil cooling abilities.

Very few people on this forum drive TDI Rovers, let alone are experts on their inner workings. If no solutions appear here you might search for a UK forum, or look on this South African forum.

Good luck and please report back what the solution is once you sort it out.
 

piper109

Well-known member
Jul 24, 2007
230
1
West Jefferson NC
I also drive a 300tdi, a 99 Disco1 SD self converted 5 years ago, with R380 and otherwise stock D1 drivetrain. I also had a problem with oil light coming on. I replaced my oil pump which is not fun as its crankshaft driven. I found that the new pump was a bit loose on the OD in the housing. It should have about 1.5 thousands clearance and mine had about 4 thousands with the new pump so clearly the alu front cover of the engine where the pump turns is a little worn. My engine has about 170k on it. I also found that the spring for the oil relief plunger was a lot shorter than the spec. I bought a new valve assembly but it turned out to be Britpart and the plunger was out of round and junk so I used the original plunger with the longer new spring. The rest of my bottom end is in fine shape and I get about 45psi on startup and about 12-15 psi at idle when hot on Rotella T6 which is thin when hot and I suspect why my light came on in the first place (5W-40). I use a mechanical Iequus pressure gauge with 1/8" line tapped into oil pressure switch port along with the switch. Oil filter and coolant lines are stock as is rad. I would recommend that you check Rave and put in a longer pressure relief valve spring, easily accessed when the oil pan is dropped. Make sure that the plunger is free.
I also saw on British forums that driving a 300tdi which has the oil light come on at idle is fairly common and some folks do it for years like that. Good luck, Steve
 

Nomar

Well-known member
Apr 23, 2004
6,078
13
Virginia
I also converted my LWB to 300Tdi about ayear and a half ago.
I used a unkown motor from the UK; the only preventive measures taken was a timing belt change and a water pump.
I use Rotella dino from where ever is cheapest.
The oil light blinks at startup for 5-10 seconds then its out.
I've never seen it illuminate otherwise.


.
 

piper109

Well-known member
Jul 24, 2007
230
1
West Jefferson NC
My apologies Jasper. I put all my dimensions in old British measurements and just noticed that you are in NL.
I am well versed in metric too. If you need explanations, I can convert :) Steve (old Brit)
 

rovercanus

Well-known member
Apr 24, 2004
9,643
244
Have you checked oil pressure in the new engine?
My 2000 D2 was getting a flickering oil pressure light. Checked pressure and everything was fine,
I was poking around getting ready to pull the front cover to replace the pump when I noticed that the harness that has the oil pressure switch wiring had a bare spot. Yup, switch wiring was grounding giving me a light.
 

piper109

Well-known member
Jul 24, 2007
230
1
West Jefferson NC
I think its pretty unlikely that a Turner supplied engine be defective. I think its more likely that his use of a 5W-40 oil is not such a good idea on a basically old tech engine and by changing to a 10w-40 or 15W-40 oil might be more suitable. I have had low idle pressure on mine too when hot, with a 5W-40 synthetic which is what I use in the wife's VW tdi and I regularly check the mechanical pressure gauge I installed. If I see it dropping I will use a different oil, more in line with what UK 300TDI drivers tend to use. Steve
 

disco baboon

Member
Oct 1, 2014
9
0
lingewaal holland
Hey guys,

thanx a lot for all your replies; as I told before, changing the oil-thermostat didn't change a thing. But changing the pressure switch yesterday did. When I started this whole fault finding episode in the beginning, I hooked up a gauge, showing me that the pressure switch was coming on correctly at around 0,5 to 0,8 bar. So I went on searching without paying further attention to the switch, assuming it was okay. But somehow, somewhere along the way it got knickered and ended up switching at 1,10 bar. So yesterday I did a long run on the highway with a new switch and a gauge installed, and the light didn't come on once. Idle pressure being around 1,1 - 1,2 bar hot. I had a chat with Richard Turner from Turner Engineering before about this and I'm thinking now that a hot idle pressure like this might not be that bad after all. It is just because RAVE states that idle pressure should be 1,76 bar, that I'm going nuts on lower readings.

I'm going to have my rad reconditioned anyway, and hope that a lower flow resistance is gonna give me a couple of tenths of bar more, and then call it a day.

to Steve the Piper 109: Thanx for your supportive thoughts; I spent 2 nights lying awake on what oil to put in after break-in, and decided that it had to be fully synthetic this time, although I've always been conservative towards it. I reread a couple of my lubrication instruction books for car techs, and the advantages for turbocharged engines are massive. so I took the thickest full syn I could get, being the 5W40.
As my pressure problems are only occurring when hot, the oil will then be in the 40 range.
I'll put in 15W40 semi syn on the next change, anyways and let you know if that changes the idle pressure a lot.

I blamed the oil pressure relief valve for a lot of things before, but it should kick in around 3,8 to 4,0 bar, which mine does (very clear to read on the gauge). so this means that on pressures lower than 3,8 bar the valve has no effect on the pressure because it is closed. On idle, no matter how weak the valve spring, it will stay closed. if not, it would also cause pressure drops on higher revs, which is not the case.

As for the oil pump: I went trough the same proces with my old engine and there is a lot of things to raise eyebrows about concerning the oil pump situation: for starters, the new pump gears I ordered back then had more play in the housing than the ones that came out. I found that 3 out of the 7 screws that hold the steel pump cover plate to the housing were a full turn loose, and as with almost all of the relief valve springs, my spring was about 12 mm shorter than the length stated in RAVE. Back then I thought to have found 3 separate causes for oil pressure drop, but when I solved all those 3 (screws/spring lenght/play) the oil pressure was still bollocks

pdxrover mech: checked it, nop... but I'll have the rad reconditioned anyways. thanks

to rovercanus: Yeah. I was hoping for wiring issues too. but it wasn't that.

Jimmyjamz: ............NO........... ....no.. no.. I just don't want that. Altough I now have all the special tools needed for the job , I will not take this engine out for the next 2 years. So, Turner engines are fine. period. I wake up at night every now and then thinking what you said though. :-(

Tanks guys, I'll post back once I got the recon rad in, and if I change my oil for something thicker.
 

disco baboon

Member
Oct 1, 2014
9
0
lingewaal holland
One more thing that would be interesting: I would like to get as many gauge readings at idle from as many 300tdi's as I can get...
Because I'm getting more and more the feeling that LR's 1,76 bar is simply too high.

Anyways, I'm gonna spend some time with my missus now, çause I'm starting to become a Land Rover nerd..

I'll keep you updated, greetz Jasper
 

piper109

Well-known member
Jul 24, 2007
230
1
West Jefferson NC
Interesting reading Jasper. Glad you found the pressure switch was a bit off and feeding your worries. What you found is very very similar to my own findings so I believe your original engine was probably fine as I believe mine is. After replacing my oil pump, finding the looseness in the housing, loose screws etc, I put everything in with the new pump and a new oil pressure gauge, filter etc. Running the engine now everything seems normal, pressure light goes out within 1 or 2 secs and frankly I came to the conclusion that my use of the 5W-40 full synthetic oil, Rotella T6 was basically my biggest problem. If I had put a slightly heavier oil in when the light went on or just waited an hour or two before pulling everything apart, I probably could have saved myself a lot of work and trouble. These engines are very well built and tend to last a very long time but their history I believe used oils that are good but not particularly modern and that the thin synthetic oils in common use today can give misleading idle pressures which can be worrisome LOL. I will continue using the synthetic Rotella T6 as it has a really good reputation and my Wife's VW diesel sounds like new after 13 years on it. I will note my oil pressures and publish them. Steve
 

piper109

Well-known member
Jul 24, 2007
230
1
West Jefferson NC
My idle oil pressures at present are about 3 bar (~50 psi) at startup with cold oil, when hot about 1 bar (~15-16 psi) or slightly above. Hot highway pressure about 40 psi.
Oil is Shell Rotella 5w-40 synthetic and engine is 20 years old and about 170k miles (272k km). Bottom end bearings are still standard.
Steve
 
Hi,
I had oil light toubles on idle last year, checked pressures and toke the same values from piper109. Oil is Shell half-synthetic Rimula R4 15W40 and my 1998 Disco has 282000km in the clock.
Checked pressure switch inserting it in a hose end of an air pressure line with manometer and regulator (as I saw in a Renault workshop manual), and found it opened at 20 psi. New genuine swich tested in this way opened at 5psi. RAVE electrical specs are 2,75psi-5,75psi for this presure switch.
Many users suffered from this trouble and in most cases this switch was wrong.

Regards