W

WatchcamP38

Active Member
Hi all,

Car had allegedly overheated before I bought it but has not for me. (97 4.6)
Took it for MOT on friday and they refused to do emmissions test as they said it was burning oil. I had not noticed so was a surprise.

Did a compression test just now and got the below results: (engine was cold)

Drivers side front to back 160,160,170,160
Passangers side front to back 160,160,155,160

Seems pretty normal?

But when i rev it over 3000 revs there is a fair amount of blue tinted smoke. Idle looked fine so hadn't noticed but it is fairly bad on rev.
Also white smoke a bit on start up and a fairish amount of water comes out of the exhaust until it gets hot.

One of my oil breather pipes is split two inches up it and missing the oil seperator (new bits in the post) - doubt this would contribute too much to the problem?

Not sure what to do next? All thoughts welcomed. Thanks
 
Are you losing much oil/water? What are the levels like?

What's the mileage? Oil burning could be tired valve seals perhaps? Water on start up could just be condensation, especially given the cold weather. Does the white smoke/water coming out clear once she's warm?
 
Mileage is 129k miles. White smoke and water does clear after 5 minute drive so that could be ok.
I was thinking valve seals but wouldnt that show up on the compression test?
It doesnt seem to be using oil or water. Hard to tell though as mot expired so not putting any miles on it but certainly the water level appears stable.
I was wondering if it had wrong oil ... Too thin?
Also although it has a decent history i am not convinced its been that well looked after in its recent history.
Worth changing the oil to see if it improves?
 
No, valve stem seals wouldn't affect a compression test. They seal the shaft (stem), the valve itself seals the cylinder at compression. Pop a rocker cover off for a visual check of them, you can also assess general condition from there, i.e. is it clean looking or full of black gunk.

Yes, worth an oil change. I'm sure someone will be able to offer further and more detailed advice but I'd put 20w50 in it and see how it goes.

Cheap to try all of the above and a good place to start.

Pull some spark plugs out as well (if you've got time check all of them), 'read' them, great indicators as to what is happening in each cylinder.
 
blackvoguebeauty said:
No, valve stem seals wouldn't affect a compression test. They seal the shaft (stem), the valve itself seals the cylinder at compression. Pop a rocker cover off for a visual check of them, you can also assess general condition from there, i.e. is it clean looking or full of black gunk.

Yes, worth an oil change. I'm sure someone will be able to offer further and more detailed advice but I'd put 20w50 in it and see how it goes.

Cheap to try all of the above and a good place to start.

Pull some spark plugs out as well (if you've got time check all of them), 'read' them, great indicators as to what is happening in each cylinder.
Click to expand...

Thanks for the feedback ... of course i should have thought about the valves sealing under pressure. what was i thinking? So seals quite likely.
I did have a good look at the plugs as i changed them today while doing the compression test. They may have been a bit too oily to be honest. Hard to tell as i had soaked the plugs with penetrating oil to get them out ... They were pigs to get out!
Will whip off a rocker cover asap and see what i find but it does seam likely to be valve stem seals? Could it be anything else?
If they are worn better to get them sorted but also would thicker oil resolve anyway?
 
Thicker oil may help, but better to get them sorted properly. An engine with that mileage will be starting to get a little tired anyway so the 20w50 should help generally. Also, a good thorough service can only be a good thing.

Run it for a bit once the new plugs are in and you've done the service, then pull a couple again and see what they look like.

I'm sure there are threads on here about changing valve stem seals without removing the heads, certain type of valve spring compressor is required IIRC.

Good luck with it.
 
blackvoguebeauty said:
Thicker oil may help, but better to get them sorted properly. An engine with that mileage will be starting to get a little tired anyway so the 20w50 should help generally. Also, a good thorough service can only be a good thing.

Run it for a bit once the new plugs are in and you've done the service, then pull a couple again and see what they look like.

I'm sure there are threads on here about changing valve stem seals without removing the heads, certain type of valve spring compressor is required IIRC.

Good luck with it.
Click to expand...

Thanks very much - will try the oil change and have a look under a rocker cover.

Not removing the heads would be useful, will look into that. Cheers!
 
The white smoke on startup sounds like a cracked or slipped liner to me or a slightly weeping head gasket which isn't bad enough to show up on the compression test. Take it for a drive - not too long - just to get it to an operating temperature (but not hot enough to boil the coolant) pull, up, crack the coolant cap (carefully) to let the pressure out and then switch off. carry on carefully releasing the cap 'til it's off and then leave it overnight. If it feels like it's about to boil (you'll feel rumbling) tighten the cap and try again another day.

The next day I bet it'll start without blowing out white smoke. By depressurizing the system when hot the coolant will not have found its way into the cylinder overnight.

As for burning/using oil add a can of Lucas Oil Stabilizer to the oil - unlike all the other snake oils (wynns, slick 50, STP etc) this stuff really does work.
 
Thanks, will try the pressure release idea.
Will have a think about adding the lucas stuff. I like the idea but will it last? Might be better off changing the seals if i find an issue under the rocker cover.
Having said that i cnt find too much on how to do it with the heads still on. Will look again tomorrow.
Cheers all for the help, much appreciated!
 
For what it's worth I had exactly the same symptoms on my '97 4.6. I also failed to notice the blue smoke until the MOT guy pointed it out. On my compression test one of my pots was down around 140 so I was pulling the heads in any case. The low compression was due to one of the valves being caked in carbon deposits and not sealing correctly. Upon finishing the rebuild with new valve stem oil seals the oil burn problem was still there. Eventually I bit the bullet and replaced the oil control rings. The old ones were a right mess. Real easy to do and fairly cheap for the completed set of rings. Certainly cheaper than the price of a third head gasket kit. No more blue smoke after that and car ran extremely well. I also seem to recall that these engines only got valve stem oil seals when new emission regs came into force. So the chances of a few old ones causing your smoke burn problem are slim.
 
Last edited:
I must admit I am leaning towards goin the whole hog.
My compression test was ok though so might not be such a good idea as it was for you?
Could I test the rings with heads off which might help decide?
 
WatchcamP38 said:
I must admit I am leaning towards goin the whole hog.
My compression test was ok though so might not be such a good idea as it was for you?
Could I test the rings with heads off which might help decide?
Click to expand...

No you can't test rings. All you can do is remove pistons and replace them. If you are burning oil you should have oily plugs.
 
Plugs were oily thinking about it. I thought maybe it was the wd40 i sprayed to remove them but it was black.
Would be oily from either valve stem or rings though i presume?
 
Wonderful, so as jt mentions i could do the valves and still find a problem.
Is it worth even trying thicker oil?
I may as well break it down and get on with it?
 
The only valid test for rings (without inspection) is a wet and dry compression test while the engine is in one piece, if compression figures are improved drastically after some oil has been squirted down each bore then the rings are shot. However compression figures in the 160s are fairly healthy given the compression ratio of the engine. Of course good compression readings don't mean that there aren't some broken oil control rings. You can check for excessive crankcase pressure by removing the oil-filler cap with the engine running and feel for pressure pulses. If there's excessive ring blowby then you'll feel it. however without knowing what it was like when the engine was healthy this is a pretty subjective test.

The problem with "wet" compression tests these days is contamination of the catalytic converters with oil, it should burn off - but there's a chance you can push an already dying cat over the edge - meeeeoooooooow! (thud!)
 
WatchcamP38 said:
Wonderful, so as jt mentions i could do the valves and still find a problem.
Is it worth even trying thicker oil?
I may as well break it down and get on with it?
Click to expand...

Really, try Lucas Oil Stabilizer, despite a recent oil change my brother's old Daihatsu sporttrak smoked visably and used nearly as much oil as petrol - it failed its MOT miserably on hydrocarbons. After a can of the above, oil usage dropped to almost nothing and the car passed its MOT!
 
StuckAgainSteve said:
Really, try Lucas Oil Stabilizer, despite a recent oil change my brother's old Daihatsu sporttrak smoked visably and used nearly as much oil as petrol - it failed its MOT miserably on hydrocarbons. After a can of the above, oil usage dropped to almost nothing and the car passed its MOT!
Click to expand...

I have nothing to lose ... Will try it, cheers!
I'll combine with the thicker oil and see how it goes.
 
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