I love my 98 XK8 and am considering replacing my Main and Rod Bearings due to occasional flickering of the low oil pressure light after high speed driving and stopped in gear.
Does anyone know if this can be done without engine removal?
The import shop I contacted says it needs to come out and would be about $2,800. I know the bearings are only a few hundred, so the cost is mostly labor.
Thanks for any info!
Dave B.

 

Yes, the engine would have to come out. Try adding a qt. of Restore, and you can always switch to high mileage 10W40. You might even change the pressure sensor located near the oil filter.

Have you replaced the secondary tensioners with the 3rd gen metal body? If not it may be that the tensioners are cracked and losing pressure at idle.

Another possibility is that the primary guides are falling apart or the shoes from the secondaries fell off and the plastic pieces are beginning to plug the oil pickup screen.

It is unusual to hear of bearing failure unless some unusual event like running on low oil or not changing the oil is involved.

 

+1 on primary timing chain guides breaking and falling into the sump.

If you have not replaced the primary and secondary timing chains, tensioners and guides, that is a much greater concern than the main and connecting rod bearings.

 

++1. And even if you have replaced them, the bits are likely still sitting in the sump.

 

Thank you RJ237 and NBCat,
I had done all the items you have suggested about 20,000 miles ago. New guides, tensioners, chains, 10W-40W oil, new sending unit, dropped the pan and cleaned debris and the thing that stopped the flickering low oil pressure light was adding a bottle of Lucas Oil Conditioner, which is kind of thick, at my last oil change.
The low oil pressure is a fairly recent development, so I would guess the original cracked tensioners and guide debris in the pan have contributed to bearing wear.
Guess I'll have to bite the bullet and get it done.
Dave B.

 

Before you spend that kind of money why not invest in the Realgauge by whitexkr and see what the oil pressure and water temp. actually are under normal operating conditions. Look at his info in post#4.

This is something every Jag should have instead of depending on those misleading factory gauges.

 

Were shorter bolts used when the tensioners replaced? Re-use of the original long bolts will lead to low oil pressure due to leakage under the tensioners.

 

Thanks WhiteXKR,
I did use shorter bolts in the tensioners.

 

I would be looking at the oil pressure sending unit first before digging into it deeper. You could be getting bad information.

 

If you get to the point of having to drop the entire pan, it is possible to change the rod and main bearings IN THE CAR. We used to call it a Hail Mary rebuild, in the old days.

First thing you do, while the engine is cold, is to replace the oil pressure sending unit, and drop ALL the main bearing caps, marking the direction they are facing, and which journal they came from. Take a super small punch(brass if possible), and a small hammer. CAREFULLY tap the side of the upper main bearing,on the side without the notch for the bearing insert, and that bearing should start coming out on the side where the notch is. This is where I move on to a PLASTIC putty knife, or spreader, cut to width, and tap until you can remove the upper bearing insert with your hand. Replacement is the opposite of removal. use plenty of assembly lube, through this whole process. This whole exercise is to protect the main Journal, on the crankshaft. You can afford a few very small scratches on the block side where the bearing insert sits, but never on the crankshaft. Install each of the bearing inserts into the main caps, and install the caps in the correct direction into the engine block. Torque them to the proper torque and move on to the rod bearings.

The rod bearings are much easier, in that you simply rotate the crankshaft, until the rod cap is at it lowest point, and remove it, and mark the direction it faces. You may gently push up each piston, to install the upper rod bearing insert, and carefully bring it down to the rod journal on the crankshaft. The connecting rods, and rod caps have notches in them also, so you do not put them in backwards.(there are stupid people out there) You torque each of these as you go.

You should have access to the oil pump strainer, and if you are able, remove it, and clean it out. If you have access to the oil pump, replace it, cleaning out the hole inside the block with carb cleaner. If you see crunchy stuff, get as much of that out as you can.

Replace the pan, and filter, fill it up with cheap oil of the correct weight. Shut off all accessories, and start her up. Let her idle until the cooling fan kicks on a few times. Look for leaks. Stop the engine, and drain the very hot oil, leaving the filter in place. Fill it with cheaper oil again. Start the engine, and let it idle until the cooling fan kicks on a few times, and drain the oil, and this time REPLACE THE FILTER. Fill it with the correct oil you usually use, maybe going up a thickness, for this first few thousand miles. Check for leaks, and if you did everything right, she should be OK.

Do not waste your time with this procedure, if the engine already has a rod or main bearing knock.

Unless the tech at the Jaguar shop, who is working on flat rate time, wants to lose, or break even on money earned, he or she will probably use this method. They will not replace the crank, unless there is damage to it.

If the crankshaft is damaged, you will be paying for a complete top and bottom end overhaul, or engine replacement, new or used. I would go for a low mileage used, because people with these cars usually take care of them. They are much cheaper than the Jaguar specialist putting bottom end bearings in them by a LLLONNG shot, and these engines are extremely long lived, after you change out the chain tensioners, and change the oil every few thousand miles.

On a side note, it doesn't matter how many weeks you leave an engine draining oil out of it, so you don't get all oily and nasty. I have worked on the bottom end of engines that have set for years, and as soon as you remove that oil pan, it is going to drip on you for the entire job......

This bottom end bearing change I have done my whole life, which was past down to me, from my journeyman, from his journeyman, from his journeyman, all the way back to the old Ford Model Ts. It works 99% of the time, unless you damage the bearing, or crank surface.. You can't do this on pushrod engines, and have the 99% success rate, because they also have cam bearing inserts, that need replacing, and they usually are the trouble makers, that start all the problems in the first place.......Hope this is helpful.....Mike

 

Care must be taken when changing to a 'thicker' oil viscosity or adding 'oil conditioners' as this can lead to future problems with the VVT units in the NA 4.0 litre engines.

 

mrplow- I suspect you have not tried this on a jag V8. The main bearings do not have separate caps, they are contained in a single casting which forms the lower part of the block. The engine must be removed to service the bearings.

 

RJ 237....No I have not, and thank you for the info. It sounds like they picked up their engineering in 1934, from Dr. Ferry Porsche, when it comes to splitting the engine, to put main bearings inside. That being the case,(PUN INTENDED) instead of a bottom end replacement I would simply replace the engine, with a low mile used engine, since it needs to come out anyway. The Porsche and VW air cooled cases, seem like much less trouble. I could have a bug engine out of the car, completely rebuilt,(rods, mains, new pistons, rings, jugs, adjust the valves, and inside the car and running in less than 3 hours. The Jag engine sounds like a pain in the a$$.(PUN INTENDED)

There are gobs of them with 60,000 miles or less, for around $750. I could have had the 41,000 mile engine, that my trans was attached to for an extra $400. It was a flood car, but an engine that was not running, when it was flooded is much easier to prepare, with a few oil changes, than having an electric pump pushing 80 litres of trans fluid through a running trans, until it comes out clear.

Most yards are willing to deal, because the engine market for Jaguar XK8s, at least around here is almost nonexistent. The transmissions are the expensive parts. There aren't many connections to yank the Jag. engine out, compared to let's say a modern Porsche 911. I have done both. Most Jaguar 4.0, and 4.2 engines just don't break.

I picked up a supercharged engine complete, delivered to my house for $600. I was going to use the supercharger assembly, including any ancillary parts for my engine, because the unsupercharged engine has thicker rods for it's higher compression of more than a full point over the supercharged version. All I would have had to do is run 93 octane or higher(if my math is correct), and let the blow off and knock sensors do their job.

Someone in Indianapolis, asked the yard where I purchased it from for my name(I'm sure money was involved). I made $400 on the deal, in 3 days. It was better than stealing for me. I'll find another one in the next year or so. Guys driving supercharged XK8s have trouble with objects in front of them.

Thank you again......I guess an old dog can learn.....Be cool....Mike