Jimmy's started doing this after a water crossing, we found no water in the oil, and after driving for a while it stopped happening. Maybe it is just a bad connection on the sensor or in the wiring?

 

Thanks Mike!

I'm hoping it's just a bad faulty connection. It only happened twice (or at least that's when I noticed it), once last week and once last Saturday night on my way back home from a friend's house. I will post back after the oil change. Thanks again!

 

If this happens while hot and idling then you may be experiencing low oil pressure. Particularly, if you are coming off of a higher speed driving (eg highway driving) and then exit and come to a stop light and experience this then I'd say you are not experincing a faulty connection.

What weight oil do you run? I'd not risk it - if you see this again start running thicker oil. 20W50 helps tired engines with a little more film on the moving parts.

If you really want to know what's going on, you can thread in a mechanical oil pressure gauge - the sending unit is not hard to get to (near the oil filter) & you can pick up a gauge relatively cheap. Now, it might be messy hooking it up if the filter is full of oil....but, it's better to catch something early before any serious damage can be done.

 

Hey Jason do you know the thread size of the sending unit is? It would be nice to have a oil pressure gauge but it would be real nice to get all the parts lined up for the next oil change.:grin Oh btw good idea!

 

What is posted below if for the distributor driven oil pumps like on my 94 d-90. For crank driven, I do not have experience...

I just suffered quite a bit of hassle from my oil pump so I have become very familiar with them as of late. First thing, Glenn, is to change out the sender unit--they are $12, and if it is good, then hell, you have a spare. Only a little oil will come out while doing this process with everything full, so don't worry about it. Have the second one handy, unscrew the one that is in there and plug the hole with your finger while you have the second one handy--no big deal. You could just take out yours and clean it and see if that works, but for $12, I find it is just as easy to swap it. Basically, all they do is have two pieces of metal separated by a slight distance and with the right pressure, those two pieces make contact causing a ground between the wire connected to it and the engine. When grounded, the light comes on.

If that does not cure it, then you have an issue--low pressure. There are a few things that cause low pressure, but the most common one is that the oil pressure releif valve is sticking--this is the larger of the two cap nuts that are on the pump (at least on my 94 D90). If it sticks, then it is sending pressure to the supply side as if it was still curing over-pressure. If that is the case, you have to unstick it--this can be done by rapping it a couple times on the large cap with a hammer if you are lucky, or more likely the case, pulling out off the cap, taking out the spring and making sure the plunger is moving full distance back and forth really easily. The problem with this is that you can loose all prime in the pump, but hell, it is really not that big a deal--just pull off the 6 screws that hold on the pump cover. (4 of these you can get out with a 12 point 8mm socket, the other two will need a 12 point 8mm wrench). With the cover off, make sure that the pressure relief valve is moving just fine. Pack the gears with vasoline, put the cover back on (if the gasket looks fine, just reuse it--if it is torn up, replace it but get off all the old material before you do so).

Now, all should be good--these pumps are pretty simple, so that should be all that it takes. If you still have low oil pressure, the next thing I would check is that the oil sump pickup tube might be loose (which is how I fried my pump in the first place). Pull off the oil pan (don't worry, it is a piece of cake)--it is held on by about 12 13mm bolts. Check that the sump is tight. Have a can of RightStuff handy for when you put everything back together (Oh yeah, you will have to change the oil for this procedure). Put Rightstuff around the lip of the sump and put it back on. Hopefully your problem is now solved.

If not, then you either have a problem with the pump gears (replace front cover) or an oil passage is blocked. Don't think it is either of these, so let's not get into it yet--my fingers are tired....

 

"If you still have low oil pressure, the next thing I would check is that the oil sump pickup tube might be loose (which is how I fried my pump in the first place)"

I have had that happen on two of my rovers now

One thing I noticed with both of them was that it would tap/rattle @ startup when it had been sitting for a while if that helps.

 

If this happens while hot and idling then you may be experiencing low oil pressure. Particularly, if you are coming off of a higher speed driving (eg highway driving) and then exit and come to a stop light and experience this then I'd say you are not experincing a faulty connection.

What weight oil do you run? I'd not risk it - if you see this again start running thicker oil. 20W50 helps tired engines with a little more film on the moving parts...

Jason, you nailed it...! That's exactly when I noticed the light flickering - coming off the highway on the exit ramp and at the first traffic light. 5W30 is in there right now (or it could be 10W40, not sure), but I will switch to 20W50 and see what happens. Didn't get a chance to change the oil last night since the oil I had in stock is 5w30 and I wanted to try your suggestion, so the 90 is in the driveway right now. I'll stop by the store tonight and buy some 20W50. Hopefully that will resolve it.

_____________________________________________

Chris,

That is an excellent write-up. I will try that $12 solution. Do you have a part # for the sending unit? Is it a dealer item only or can I get one at NAPA or PepBoys? Thanks again.

Mike or CVC, maybe the write up that Chris did can somehow make it to the tech articles in the future.

Dave, where exactly was the "Tap/rattle" coming from?

Thanks to all that responded. I will keep you guys posted!

 

"Dave, where exactly was the "Tap/rattle" coming from?"

From the top end, guessing it was lifter/rocker noise due to starvation @ startup

 

Mike or CVC, maybe the write up that Chris did can somehow make it to the tech articles in the future.

marked already for the FAQ!

 

Glen,

That is the worst-case scenario for oil pressure in an engine - a good amount of the oil is up in the engine somewhere, hot, and suddenly RPMs drop. You'll generally experience your lowest oil pressure at that moment. After a little while the oil pressure will recover somewhat.

5W30 is pretty thin IMHO for an engine with some years on it. 20W50 will help boost the oil pressure, though depending on how cold it gets in your part of Joisey in the winter you might want to consider 5W50 synthetic.

Even if you get the oil pump in tip-top shape it just may be basic bearing wear. If there is too loose of a tolerance between the reciprocating parts and their bearings the oil pump will not be able to produce enough of a volume of oil to maintain high enough pressure.

It sounds to me, barring a problem with the sending unit or the pump itself, that you are at the very beginnings of signs of engine wear. Getting the oil pump in top shape (possibly a rebuild - the pump is external, which is *nice* from a maintenance standpoint) and using thicker oil can extend the life of the engine for quite awhile.

I am paranoid about oil pressure - it's one of the most important indicators of an engine's health.

Mike,

I don't know the thread size on this engine, probably pipe thread (NPT) - but I've done that on several engines over the years, particularly for testing purposes (I used to carry a mech gauge with me to test used vehicles I would consider buying and thread the thing on right there where it's parked). Most of the time in vehicles I keep for awhile (which don't have a gauge) I end up putting a brass "T" on the sending unit opening, move the the idiot light sender to one opening in the T and run a mechanical oil pressure gauge in the other. Sometimes if you have only the gauge you don't notice a drop in pressure which the idiot light would have alerted you to, so IMHO it's best to run both. This is also on my list of mods that my D90 will get eventually.

 

OK all this thread has a good chunk of info about the oil pump in it so time to add some more.

As you guys may know while I was down in PA I lost oil pressure in a mud hole, well I just pulled the oil pump off to see if the releif valve was sticking. When I went to pull it off I noticed that the adaptor for the oil coller lines (the part between the filter and the pump) was loose on the pump. When I got the oil pump out I found fine sandy mud inside of the pump, not a good thing, when we changed the oil on the trail it was dirty but not as much as what was in the oil pump, my guess (hope) is that the sand clogged the pump and blocked it from getting to the rest of the engine.

Now for my problem, I went to pull the 2 gears inside the front cover off after I got the pump off, the pasenger side gear slid right off, but the drivers side one will no budge, I wiggled it back and forth with my fingers for a while and it slid out about 1/4", but I did notice that the shaft inside the gear also slid out at the same time. The other shaft did not come out at all, should the shaft come off?

After replacing the oil pump and gears I plan on running the oil pump with a drill to prime everything just to be sure it all works.

Any advice would be greatly appreicated.

 

Mike,
The one shaft in the pump is stationary, the other is attached to the gear and slots into the distributor to drive the whole works. You can shim the oil pump spring to get a bit more pressure or Landrover offers a pump rebuild kit with all of the consumable parts. The sending unit is British straight Pipe thread and not really compatible with any off the shelf sending unit that you can buy. My solution was to drill and tap the bottom large plug in the oil pump with 1/8NPT and use some short pipe and an elbow to allow me to get a VDO sending unit into it. It has been working great for about 50K miles now. These engines do not run a lot of oil pressure....only about 26psi at around 2000 RPM hot...I don't have an exact spec at the moment, the manual is at the shop. I would just fill the oil filter and pack the gears with petroleum jelly, lubriplate, or assembly lube...it will reprime...don't use axle grease, it will not dissolve into the oil and may plug the oil pickup or lifters. To turn the pump with a drill will require making an adapter and removing the distributor. My oil of choice is 15w40 Shell Rotella T medium duty truck oil...it has a good additive package, is relatively inexpensive, gives good pressure, and with 2 Optimas in parallel pushing 1600CCA, it starts no matter what.
Cheers, Rob

 

Thanks Rob! I made an adapter and removed the distributor already so I could make sure it primes before I try and start the engine. I like the idea for the gauge, I'll pick one up and put it one the pump like you said. So then the other gear does not come out? Or does the shaft come out with it?