Defender TD5 Engine Oil Pressure and Level

Defender TD5 Engine Oil Pressure and Oil Level

I recently noticed that the oil warning lamp is taking longer to extinguish on starting the engine than previously. With a cold engine and having stood overnight, it can take as much as two seconds before going out. The engine starts easily enough and the performance appears normal.

On checking the oil level (after standing overnight), it was a good ½ inch higher over the full mark on the dipstick. Starting the motor and letting it run for 10 seconds then switching off and re-checking the level, showed it to have fallen back to precisely on the full mark. To me this suggested that a lot of oil is draining back to the sump overnight and would possibly account for the time taken for the oil warning lamp to extinguish - presumably whilst the oil filter and galleries are being refilled before pressure is established.

The oil filter has been changed in case the anti drain back valve had failed but this has made no difference and the problem remains.

I’m beginning to wonder if there’s some sort of internal oil leak from the galleries (maybe a seal failure) or excessive wear has occurred in the crankshaft bearings - though there’s no unusual noises. The vehicle has only had light use and is always driven carefully and never flogged. Mileage is 30,000 and just out of warranty.

I’m curious if anyone else has experienced this? I did noticed one report with similar symptoms following return of the vehicle after it had been serviced but there was no follow up posted.

xxx-kev said:

Defender TD5 Engine Oil Pressure and Oil Level

I recently noticed that the oil warning lamp is taking longer to extinguish on starting the engine than previously. With a cold engine and having stood overnight, it can take as much as two seconds before going out. The engine starts easily enough and the performance appears normal.

On checking the oil level (after standing overnight), it was a good ½ inch higher over the full mark on the dipstick. Starting the motor and letting it run for 10 seconds then switching off and re-checking the level, showed it to have fallen back to precisely on the full mark. To me this suggested that a lot of oil is draining back to the sump overnight and would possibly account for the time taken for the oil warning lamp to extinguish - presumably whilst the oil filter and galleries are being refilled before pressure is established.

The oil filter has been changed in case the anti drain back valve had failed but this has made no difference and the problem remains.

I’m beginning to wonder if there’s some sort of internal oil leak from the galleries (maybe a seal failure) or excessive wear has occurred in the crankshaft bearings - though there’s no unusual noises. The vehicle has only had light use and is always driven carefully and never flogged. Mileage is 30,000 and just out of warranty.

I’m curious if anyone else has experienced this? I did noticed one report with similar symptoms following return of the vehicle after it had been serviced but there was no follow up posted.

Click to expand...

Alright Kev,

You should always switch off the engine for up to 5 mins before checking the level to allow the oil in the cylinder head time to drain back into the sump otherwise the reading on the stick will be incorrect.

Read your owners manual on the correct procedure, my 300tdi oil level should only be checked when the engine is warm and must have been switched off for about 5 mins, yours might be different but worth checking, do it how the engine designer does it.

Might be worth you checking what oil you're using, it should be 5w/30 which is quite thin when cold and should get round the engine fairly quickly.

If when you check the oil in the correct way and it is over the max it would be a good idea to drain a bit out otherwise the increased crankcase pressure might force excessive amounts of oil into the combustion chamber which will not do your cat,egr or lambda probe any favours

Could maybe be the pressure relief valve sticking (I think engines still have these - last did one on an Austin A60!). A sticky valve causes excess pressure when running and too little on idle. Impossible to detect without a pressure gauge - in your case it might be worth fitting a gauge anyway to check what's going on. they are easy to fit - usually on a T-piece in the pressure switch socket.

This can be caused by the following problem with the injector oil seals.

The injectors on a TD5 do not have an external fuel feed. They are fed via a drilling and individual galleries in the cylinder head. The injectors therefore have two critical seals:
A copper washer to seal against the combustion chamber and an O ring which seals the injector into the fuel gallery.

The fuel is fed to the galleries at 60psi and under normal conditions the O ring is perfectly capable of sealing this pressure.

However if the O ring is damaged on installation, or has been hardened by overheating, the engine can leak fuel under pressure into the camshaft carrier and thus into the engine oil causing dilution and increased oil levels.
This is by far the most common problem and can be solved by fitting new injector seals ( always change both the O ring and copper washer ) and by applying a smear of clear silicone to the O ring on installation.

Secondly if the copper washer seal fails it will cause excessive pressure in the injector oil gallery which will force fuel past the O ring with the same results. As the engine warms up the copper washer often reseals with a noticeable reduction in engine noise and no more fuel leaks until things cool down again. This is caused by not fitting new washers when changing the O rings. If you dont have new washers then heat the old ones to cherry red before quenching in cold water. This softens them with more chance of a good seal being achieved.

Occassionaly if an engine has been severely overheated due to lack of coolant the internal galleries in the head can crack leaking fuel into the oil. There are none of the normal symptoms present such as coolant in the oil or lack of compression when this has occured. There is no way to repair this other than a new cylinder head. The only way to diagnose this is to change the injector seals and monitor the oil levels. If they continue to rise then you have your problem nailed.

The consequences of this problem are that the engine oil is diluted and the levels are raised often by as much as double in bad cases. Engine oil will smell strongly of diesel.
The engine does not appear to suffer any undue internal wear but the turbo bearings will fail in a very short time as they are highly stressed and run at much higher temps - relying upon oil viscosity to maintain clearances and prevent wear.
Also engine oil seals will be under extreme pressure due to the raised oil levels and will eventually fail. Oil foaming will also be present which may affect oil pressures from the pump.
There is also a risk of the engine oil being forced past the piston rings and self dieselling may occur with engine destroying results.

I hope this helps as I had to discover this the hard way. I destroyed two turbos ( the second one in under 1000 miles ) before solving the problem on my 100K miles TD5. On one occassion I drained 13.5 litres from my engine after filling with 7.5 litres and driving 1500 miles. My problem was the cylinder head but I have no idea how long the problem had been present as the previous owner was not mechanically minded.
I'm now paranoid about my oil levels.

Hi Shifty1962

I just read your post on 01/11/2008 on: Defender TD5 Engine Oil Pressure and Level.

Although I care a lot about my landrover I'm not very technical, but am trying to learn more and therefore my post.

I have a Defender 90 TD5 XS (2004) and discovered today that I have an oil leak and diesel leak at the same time. Over the last 2 weeks, I started seeing small deposits underneath the car. At first I didn't pay much attention to it. I have off street parking so I thought it can't be the landie...must be another car. Anyway, after monitoring it closely, I realised on the weekend that it was the land rover. At first I thought it was a oil leak. However after looking at the whole thing a bit closer, I was surprised how 'watery' and light in colour the oil was. So I had someone looked at the car today and the problem was explained as follows:

There is a small oil leak at/through the 'roco cover'...not sure I have this right. Not far from here is a diesel valve, on the left hand side of the engin. Diesel is leaking through this valve diluting the oil.

As you can see form my explanation, I'm confused and not sure what that all means. That's why I was trying to read up a bit more and saw your post.

Reading your post, I have to say that my oil levels have been quite high lately and I have not added oil to the engin for a long time...especially considering that I have an oil leak. Could it be that the diesel leaks through the valve into the oil therefore the high oil levels and due to the high oil levels an oil leak with diesel in it has been forced?

In any event, I was told the valve has to be changed as this is a problem that can get worse quite quick and can result in being quite serious. Is this the case?? and do you maybe know to which diesel valve is referred to here?

Any assistance in this matter would be highly appreciated.

The only thing I can think they are referring to is the fuel regulator that is bolted to the left hand side of the engine.
I dont see how any diesel could get into the engine oil via this way as there is no direct connection to the oil ways. If it has failed you would get over pressure in the fuel galleries that feed the injectors which may possibly "blow by" the injector O rings.
Failure of the fuel pressure regulator can be measured by checking the fuel pressure which should be about 60psi. Your local garage should be able to do this.
If this checks out OK then it is more than likely either an injector seal problem or more disastrously an internal fuel gallery leak in the cylinder head.
Sorry for the bad news but I changed all the same parts (because they were cheaper) before having to concede that my cylinder head was scrap.

Hi, thanks for the reply and the advise.

As long as I get the problem before it gets worse and worse. At least I have a better idea what to look or ask for. I'm in Dublin so by some chance I can ask someone to look at this before Christmas...Not very hopefull though.

This might help.

1. Gasket
2. Housing
3. Bolt
4. Fuel feed union and pipe
5. Fuel return union and hose
6. Fuel temperature sensor
7. Bonded seal
8. ’O’ ring
9. Circlip
10. Fuel pressure regulator
11. ’O’ ring
12. ’O’ ring
13. Gauze filter

The fuel pressure regulator is located in a cast alloy housing which is attached to the rear right hand corner of the
cylinder head with three flanged bolts and sealed with a metal gasket. Two ports in the housing connect with ports
in the cylinder head for fuel pressure feed and return. A gauze filter is located in the pressure feed port in the
cylinder head, and filters the fuel before it reaches the injectors. The filter is a fit for life item but can be changed if
required. An ’O’ ring is located in a recess in the cylinder head and provides additional sealing for the pressure
feed port between the gauze filter, the cylinder head, and the housing.
A union and pipe is attached to the feed port in the housing and connects with a quick release coupling to the fuel
pressure feed pipe from the fuel pump. A second union and hose is located in the return port and provides the fuel
return connection to the fuel cooler. A third port provides location for the fuel temperature sensor, which is sealed
to the housing with a bonded seal. The fuel temperature sensor is used by the ECM for engine management.

Thanks.

It certainly helps. I'm slowly starting to get a picture of how the system works and what might be wrong...or where could be potential problems. Thanks again for the help.

I'm not finding any land rover dealer that can look at this so I might have to wait till the 1st week in Jan. Let's say it is the fuel valve that failed, is it possible that the valve itself can leak diesel? Although, after reading your posts I'm now not so sure that the valve is leaking, because of the fact that the small oil leak underneath the car is a bit diluted with diesel. In addition to this, where is all the diesel going if it is the valve leaking...given the small damp patch underneath the the car?

I think your suggestion that the leak is possibly at the injector seals or worse the cylinder head is more realistic.

How safe is it to drive now, given the leak could be at the valve or the cylinders? Should I just let the car stands as much as possible?

The diluted engine oil does not lubricate the turbo bearings adequately so if you drive around at high engine speeds the turbo will destroy its bearings quite quickly. This is what happened to me.
However if you only use it for short slow engine speed (less than 2000rpm)journeys you may be alright.
I'm told that the engine bearings can manage the diluted oil but I'm not so sure.
I'd recommend you dont use it until you can get it fixed as you may be causing more damage and more expense further down the line.
This is a known problem with the TD5 engine but Land Rover are not interested. Later cylinder heads are supposedly modified to prevent this problem but I've yet to find out what changes were made.

I think I'll play it safe and get it fixed.

Hopefully it's either the fuel regulator or the injector seals...and not the cylinder head! Thanks for your posts again. I have a better idea now of what's going on.

Hi guys, I have a 300 Tdi and discovered the other day that I have no oil pressure. Is there any way of determining if it is the oil pump without opening up the timingbelt casing??

Hi, did someone by chance had and resolved the problem the original poster had?

cosden365 said:

Hi, did someone by chance had and resolved the problem the original poster had?

Click to expand...

I don't think any of those people post any more, as the thread is from 2008.

But from memory, diesel in the oil on a Td5 is usually caused by a cracked head.

But as I haven't had anything to do with Td5s for some years, I suggest posting your own thread on the subject in this forum.