1998 Oil Leaks
 

Hey - so I already posted on another thread about my plans to replace the valve cover gaskets and cam plugs on my 1998 V6 (all the parts are on order and I'll tackle it this weekend). But essentially, I'm burning enough oil to where after a few thousand miles after an oil change, I start running low, not enough that my oil light comes on, but if the high and low fill line represent two quarts of oil - I'm burning about a quart.

I'm not getting any smoke from the tailpipe, during running, maybe occasionally a small puff on startup, but not sure if that's condensation.

If I look in my engine bay, it's clear there's a good bit of oil coming from the valve covers, my engine and my skid plates are pretty well coated with nasty oil, and sometimes in the mornings, there's a small bit of smoke that comes from my engine bay after driving a few minutes, and a burnt oil smell, like the engine is heating up and cooking off the oil.

Will the valve cover gaskets etc. solve all of this? Or should I be looking at something else? Should I be concerned that the engine is burning oil or is this most likely just the leaks?

I would start with replacement the VCGs, removing and resealing the semi circular plugs, the cam plugs, clean it up well and then see if you are leaking oil anywhere else.

The difference between the high and low marks on the dipstick is approximately 1 quart. How much do you have to add?
By the sounds of it you're down 1/2 a quart after a few thousand miles.

Nothing wrong with that. Even 1 quart wouldn't be the end of the world.

OK - in my other car the dots represent two quarts. So, good to know.

What I'm trying to assess is if I can lose that much oil from valve cover leaks or if I should be exploring other possibilities, namely because the valve cover fix is reasonably involved and if there's something I should do "while I'm in there" I appreciate the heads up.

I'd be shocked if you were losing 1 quart from the valve cover gaskets. I mean, there's be puddles of oil everywhere if you were. I suspect your engine is burning a bit of oil, which normally means the piston rings are a little bit tired. Not a big deal on these engines though, they can tolerate burning some oil and running a tad bit low and keep on truckin'.

Seems like a lot of oil to lose through a valve cover. My 97 manual says there are 1.3 quarts of oil between the low mark and the high mark on the dipstick.

Any chance it's coming from the oil cooler gaskets?
I think that's where mine is originating...leaves quite a bit of oil underneath.

I know it can be maddening to try to find the source of an oil leak.

I had a camshaft seal leaking, and for the life of me, I could not locate it, until I pulled off the timing belt cover. Even then, the source was still questionable, until I removed the cam pulley and the cover behind it.

Keep in mind that leaked oil will always travel downwards and toward the rear.

It is very helpful to spray down everything in your engine bay with something like Simple Green, let it set a few minutes, then hose it off. After the water dries and you have driven it some, fresh oil will be much more visible.

No idea really. I know my valve covers are leaking because the top of the engine and alternator have significant oil gunk all over them. When I rebuilt the alternator I had to clean it out pretty thoroughly. In the mornings the engine bay has smoke coming out and a burnt oil smell but nothing out of the tailpipe. there’s also a ton of gunk on the skid plates and the underside of the transmission. I always assumed my gaskets were leaky.

I was going to say @Kyngfish if you can take a couple of pics and post them, we may be able to help out further. But once you tackle the gaskets and all it entails, then see if you are leaking elsewhere.

I have seen oil literally running out of the valve cover because the gasket was nonnexist, probably for years.

So I think when I measured this morning I hadn’t waited long enough for the oil to flow back into the pan. I just measured cold and it was slightly above halfway the marks on the dipstick. I’m still definitely leaking oil but maybe not as much as I thought.

As I mentioned - I’ve always sort of had that bitter oil smell after a drive but lately it feels worse. I’ve gone ahead and ordered the gaskets and I’ll tackle the job this weekend and post pics. Appreciate all the feedback.

You're right, I was going with Imperial quart which is 1.1.

I see it's 1.5 if it's the 4 banger.

Kyngfish, most of your oil loss could very well be the VCGs. I had bad VCG leaks in my '97 for a couple of years. I had a lot of oil accumulation on the skid plates like you are describing, and had a lot of smoke coming off the exhaust collector.

After I replaced the VCGs (and the spark plug tube gaskets, etc.), I noticed I used a lot less oil between changes. I am still losing a little, but probably about 1/2 to 1/4 of what I was losing before, and I have long oil change intervals (5-6k miles) because I use synthetic. Pretty good considering my mileage!

Check out Timmy the Toolman's valve cover gasket replacement video on YouTube, it was super helpful. Make sure to replace/reseal the half-moons and the cam plugs while you are in there, you may be losing a lot from those places as well.

Yes, thanks. I've ordered the gasket kit and the Toyota brand gasket fluid for the half moons. I've read through a few of the write-ups, not clear on if I have to drain coolant or not. I'm assuming that there's coolant flowing through the manifold, but with the engine off, I'm not sure how much there will be in there...

It isn't required to drain coolant before changing VCG's. When you remove a piece of plumbing (not sure of the name) from the intake, you will get a few thimble-fulls of coolant running out, but that can be caught in advance, or cleaned up with a rag (or blown off with an air compressor). Really nothing to worry about.

My first thought was to drain maybe a quart of coolant to prevent that, but I doubt that would draw the coolant out of that upper plumbing.