Your questions answered: Engines, breathers, and Police P38s


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13 April 2024
Ex-Police P38 can be a good investment : credit: © Ed Evans
Our expert advice on 200Tdi oil, 19J breather, Series engine swap and ex-police P38 purchase

Military spec breather system for 19J diesels

In Richard Hall’s recent article in LRM magazine he mentioned the 19J’s notorious breathing issues, and fitted a modified breathing system based on a cyclonic oil separator that had been developed by the British army. He said he had all the bits on the shelf, but sadly gave no further details.

I am keen to look into this as I still have the original 19J engine in my 1989 90, which also suffers from an oil saturated air filter. Could LRM provide more information including how to fit such a system as I’m sure I’m not the only one still running the vehicle on its original engine.
Anthony Kent

The military-type engine sump has a return pipe stub

Richard Hall replies: A modified breather system was fitted to many military 90 and 110 vehicles with the 12J and 11J (2.5 non-turbo) engines. The system can be fitted to the 19J turbodiesel to reduce its tendency to fill the air filter housing with oil. It consists of:
• Oil separator on a long steel bracket which attaches to the rear two bolts on the fuel pump mounting plate.
• Sump fitted with a return pipe stub on the right-hand side next to the front propshaft.
• Large bore hose from the oil filler cap to the breather.
• Large bore hose from the top of the breather assembly to either the air cleaner or inlet manifold.
• Smaller bore hose from the bottom of the oil separator to the sump.

There are at least two different sump designs. One has the drain plug on the propshaft side, the other on the exhaust downpipe side. With the latter type, clearance between the drain plug and the 19J exhaust downpipe is very limited and you may need to put a spacer between the downpipe bracket and the engine block.

The bracket-mounted oil separator system connects to the air cleaner, oil filler cap and sump stub

The system is simple to fit. The sump can easily be removed from underneath the vehicle, with plenty of clearance above the front axle. On a 19J turbodiesel you may need to make up a new pipe from the separator to the air cleaner using oil-resistant three-quarter-inch inside diameter hose. Never connect this pipe to the inlet manifold on a turbodiesel.


Series engine option – Tdi or original?

I have recently bought a Series III 88in with a 2.25-litre diesel engine. I plan on doing off-road days with it and general useage most weeks. Just wondering if the 200Tdi conversion is worth doing and is pretty straightforward. I have been told it does improve the Series vehicles when done. I will need to remove the body to do some work on the chassis of the Land Rover. I have previously put a Subaru engine in a VW T25 and that’s been a pain, but worth it.
Andrew Matthews

​​​​​​A machine with potential. Whatever the outcome, brakes, steering and suspension will need to be spot-on, especially given the extra thrust if a Tdi is fitted

Andrew Varrall replies: The 200 or 300Tdi conversion used to be well worth doing when donor engines were plentiful and cheap. Unfortunately, they are getting harder to find and thus more expensive. I think you would find a 300Tdi much cheaper than a 200, even though it is slightly more difficult to do the conversion.

Before spending thousands of pounds on a conversion, I would consider taking some time to be sure your current engine is running as well as it can. A 2.25 in good condition and set up well is nowhere near as bad as its reputation would suggest, and there are a few easy mods to help with the power slightly. To ensure the best from the SIII engine, make sure there is no wear in the timing chain or the injection pump drive system, and that the timing is set exactly as the Land Rover manual states. It helps to have the injectors tested and to confirm they are spraying correctly. Ensure the air cleaner is well serviced (the oil bath system is rarely looked after) and that the fuel filter is regularly changed. You can replace the solid engine fan with an electric version, and there is always room for gas-flowing the cylinder head. If you carry out all of that work, you may be surprised by how much more responsive the vehicle is.

All that may sound like I’m against engine conversions, but I’m not, and I do have a SII with a 300Tdi engine fitted which makes it drive very well. But I’m just aware that this has devalued the car slightly and that, with today’s prices, it would be necessary to do a lot of miles to warrant the cost of doing the conversion. If you do work on the original engine and still decide you need more power, then you will not have wasted your money because a really well sorted 2.25 diesel engine sells for very good money at the moment.

If you go down the conversion route, then leave as much of the bodywork on as possible, just remove the front wings and be prepared to test fit them and the radiator pack at regular intervals whilst positioning the engine. You will need the bulkhead and the back body on to make sure the position of the engine and the routing of the exhaust are correct – these are the only tricky bits of the conversion.

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Pick of the P38s

I’ve seen a Range Rover P38 for sale extremely cheaply, but with just over 200,000 miles on the clock. It’s an ex-police car and everything seems perfectly okay on it and it drives really well. Everyone tells me the P38 is unreliable and will cost a fortune in repairs, but I would love to own a vehicle like this, and this is the only way I can do it financially. Am I heading for bankruptcy?
Greg Ashton

Maintained to the hilt and always ready for action. Any P38 leaving the force should be a good buy.  Let’s hope it stayed in good hands

Ed Evans replies: An ex-police wagon with 200,000 miles and a low price could be a good move. Police P38s weren’t hacked around the city streets, they were used by motorway patrols covering big distances at reasonable to high speeds and were maintained to a very high standard. Brakes, engine, transmission, suspension and steering would have been diligently maintained because these vehicles had to be permanently ready for an instant and unexpected emergency call or long distance pursuit at high speed with no risk of failures or underperforming. The mileage is high, but it is quality mileage with the engine mainly at working temperature, being driven properly by professional drivers. The same car owned by someone who used it for trips to the shops for just half the mileage would have suffered from numerous stop-starts and cold engine running which accelerates engine and transmission wear.

Of course, this P38 will have been out of police hands for a few years, so it’s important to consider its subsequent use and maintenance. It would be good to see evidence of recent servicing. Also, go to the DVLA website to check the MoT history, which may give an indication of how many miles it’s done since the police finished with it. Repeated MoT advisories under subsequent owners might indicate neglect, whereas straight passes can suggest it continued to be looked after.

And P38s are not unreliable if they are driven and maintained correctly, nor are they any more expensive to fix and service than other Land Rovers of the era. So you’re in with a chance here.


Oil for a 200Tdi

I’ve got a 1993 200Tdi Defender. The recommended 15W40 mineral oil seems pretty difficult to get hold of, can you recommend an alternative?
Mark Kirton

The 200Tdi is one of the best engines and deserves the right oil. Always pay for a good brand of oil, and fit a quality oil filter

Andrew Varrall replies: 15W40 oil is fairly readily available by mail order from a wide variety of different makers and suppliers in either mineral or semi-synthetic forms. I have always used either a 15W40 or 10W40 in the Tdi engines, usually semi-synthetic because it is more readily available, and I have never had a problem with one of these engines because of lubrication.

That said, if you look in the handbook there is a vast array of different viscosities that Land Rover says are suitable, depending on the ambient temperature of the vehicle location, anything from 5W30 in cold climates to 25W50 in hot climates. It did specify a CCMC G5 rating which has since been superseded by ACEA A3 in more modern oils. These ratings are fairly complicated to explain but, basically, the rating specified means it is suitable for high revving engines with fairly long service intervals. The Tdi engines really are one of the last engines where the manufacturer effectively specified a whole range of oils.


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