3.5 TJ high oil consumption

[wasanne]

Hi Fellas. I have a 99 TJ 3.5 auto solara sedan with 235000 on the clock that went from using no oil between 10000 K services to using 1 litre every 700 kms almost overnight. The valve stem seals were done around 30000 Ks ago as they were obviously worn, blowing smoke on start up. No oil usage since then until now. There is no sign of smoke during start or accelerating from standstill at traffic lights. I have followed the car several times for around 5 Ks through town with no sign of smoke. There are absolutely no leaks at all. The car lives on a painted floor so leaks would be obvious. About 1 month after it started to use oil I had an injector fail open and I limped the car home for about 5 kms but if that has caused a problem then maybe the injector was leaking over that month period without any symptoms. The worst effect I could see that having would be washing the oil from that cylinder but unless that has damaged the bore or rings I can't see it being the problem. I went from using Castrol magnatec 10W-40 to GTX high mileage 15W-50 but made no difference to oil usage. Now after all this rambling my question is: Can you replace rings and big-end bearings in situ. I didn't want to have to pull the engine out. After reading some comments here supposedly you should get up to 400000 out of rings on these engines so I thought a quick hone and new rings may be the simple fix. The missus wants to get rid of it because she doesn't want to waste money on it but the car is immaculate and we can't afford anything much later which will have its own problems anyway. Any suggestions?

[wasanne]

Forgot to add that while chasing this problem I replaced the PCV valve and hoses and cleaned inside the rocker covers. Cheers.

[mcs_xi]

Forgot to add that while chasing this problem I replaced the PCV valve and hoses and cleaned inside the rocker covers. Cheers.

Have a look at the gearbox side of the engine. Check the dizzy, and front cam bung seal are not leaking. It is very very common for them to piss oil from there. same for the spark plug tube seals.

If you have done an oil change, also check the sump plug seal.

Mike

[wasanne]

Thanks Mike. Did the dizzy O-ring and the cam bungs chasing minor weeps. Also did the rocker covers and the spark plug tube seals. All of these had minor weeps but not enough to drip on the floor. There is not a drop of oil to be found anywhere on the exterior of the engine or underbody of the car. I went to a lot of trouble to stop any leaks and the worst were mere weeps at best. It has to be burning the oil and since the symptoms don't suggest valve stem seals then it must be getting past the rings. The problem is that it didn't creep up it just all of a sudden started using lots of oil. the question still remains whether or not you can do the rings without pulling the engine out.

[Spetz]

Most people would just swap the motor rather than do piston rings.
Especially to something newer/better like the 3.8

[wasanne]

Thanks Spetz. Is there any mods required to fit the 3.8 or will it just drop straight in. Open to all options at this stage.

[leadfoot6]

Bellhousing bolts, engine mounts, hoses, alternator, starter motor, accessory drive belts and such are "bolt on" on a FWD TJ.

However, the 380 coil packs need to be removed and the TJ 3.5 distributor and ignition leads need to be swapped over.

To do that, the upper manifold on the 380 replacement engine needs to be removed/reinstalled.

From memory, the lower sump also needs swapping over.

Therefore, it is not just a simple swap, but not overly complicated either.

It would be worthwhile only if you plan on keeping your car for a long time in order to amortize the 380 purchase/conversion costs.

My TL AWD(the AWD conversion involves a fraction more work than a FWD) was converted last year and I have experienced perfect reliability with all aspects of the conversion but the considerable costs that I incurred to purchase a very low kilometer replacement 380 engine will be spread out over at least 5 more years(probably more).

By doing things this way, I have avoided the impending need, and cost, to replace timing belt, tensioner, water pump, rocker cover gaskets, spark plugs, valve stem seals/valve guides etc.

The work was carried out at forum sponsor MitsFix's workshop in Melbourne who is able to freight fully prepared replacement 380 engines Australia wide at a good price.

He can supply 380 engines that are, indeed, ready to "bolt in".

More information here(with a price guide that would need updating):

https://www.aussiemagna.com/forums/sh...d.php?t=104151

Contact Mal on :

1300 300 274

In an otherwise well maintained car, you should get quite a few years extra satisfactory service by doing a 380 swap using a suitably prepared conversion engine.

The above being said, however, if I was in a "short of money" situation and being faced with the prospect of spending considerable money on an otherwise low retained value car, I would just keep driving it as it is and keep topping up with cheap $4 per litre engine oil:

https://www.supercheapauto.com.au/on...&sz=12&start=5


provided the oil consumption did not get much worse and the spark plugs did not become fouled.

IMO, the procedure of replacing rings/bearings "in situ" is fraught with potential risk.

I don't recall ever seeing anyone attempting to hone cylinders with the heads and crankshaft still in place.

It might be possible( I would not ever contemplate such a procedure myself as being sensible), but as noted would have to be considered highly risky as so many aspects could generate a "fail" - unless you are very experienced in these tasks.

If you were very experienced, you probably would not be asking for advice about these things here.

P.S. Have you carried out a compression test on the front bank of cylinders and/or a "leakdown" test?

This site:

https://dannysengineportal.com/valve...signs-testing/

provides useful engine diagnosis tips.

P.P.S. The middle ground is, of course, a second hand engine from a local wrecker with some form of parts warranty.

Ranging anywhere from $500(somewhat risky) to $1,000(should be good) plus fitting.

[wasanne]

You can't drop the pistons out through the bottom. They have to come out from the top meaning the heads must come off. That part is easy, the part I am not sure of is if there is enough room to remove the rear pistons past the firewall and get a drill in there with a hone attached. Big end bearings shouldn't be a problem but I think the main bearings would be a problem getting the upper halves out and new ones in without damaging front and rear seals as that is all that would be supporting the crank once the main bearing carrier is removed. Just guessing here, hence the questions. I have a VRS set here I bought ages ago so I probably would only need rings and bearings and a sump gasket. The cost of fitting a 3.8 overcapitalises the car and is money we can't really justify at the moment. It looks like a big job to pull the engine and tranny as a unit so thought the in-situ idea was worth a shot.

[leadfoot6]

Surely, doing all the work that you are proposing makes it common sense just to pull the motor and replace it with a reasonable cost hot run tested item with a limited warranty?

AFAIK, engine hoists are available for hire from Kennards etc.

P.S. And as asked above, have you tried any diagnostic tests in an attempt to find the cause(s) of the oil consumption problem?