A while back my repair shop told me that the oil leak on my 1996 Concorde 3.5L was coming from the head gasket. They said it was not causing any other problems with the engine. I've been checking the oil and antifreeze and the levels and appearance are normal.
I can see where it looks like oil is leaking at the top rear right hand corner of the block on the passenger side. It had been dripping a couple of drops each time I park. I can always smell burnt oil after I park, probably from it getting on the exhaust. I have my suspicion that it might be getting worse. I'm going to put the car up on ramps and see if I can get a better look when I get a chance.
I would like to get opinions on what I should do. I guess replacing the head gaskets would be the most obvious solution. The car has 136,000 miles on it. I've only had it about 3 months, so I don't know what care it had receive throughout it's life. The engine seems to be in good shape. There is plenty of power, no smoke out of the exhaust, starts right away and doesn't seem to burn oil. The engine is smooth and powerful out on the open road. There is a slight roughness at idle, but I figure it is normal for an engine with this many miles. I did run Seafoam through it a couple of times.
Would it make sense to only have the head gaskets replaced? Or would it make sense to have anything else done to the engine at the same time. I am afraid to spend a lot of money to get the head gaskets replaced only to have the engine die from some other cause in the near future. The shop at the time, guessed it would cost around $900 to replace the head gaskets. Or I can just live with the oil leak and keeping my pan under the engine in the garage.
Last edited by msmcintosh; 01-31-2008 at 05:49 AM..
I have never heard of this on the 3.5. Are you sure its not the valve cover gaskets? I replaced mine with the Ferlpro set. No leaks since. Also the roughness maybe the lower intake gasket, common on the 3.5. Felpro makes a kit that covers the intake and valve cover gaskets. Not too difficult.
The valve cover gaskets have been replaced by the shop a month ago. I brought it back because it was still leaking oil and that's when they concluded it's the head gasket. I'm hoping they are wrong and it is something simple.
When I get home today, I will put the car up on my ramps and try to degrease the area and see if I can get a better look.
Yeah, lightemup said I may have a problem with my intake gaskets. Especially after I had some occasional misfires on cylinder 5. I just haven't gotten the courage to take it apart and it hasn't misfired since we discussed it. The next time I get a misfire, then I'll have to do it for sure.
I tried to examine the backside of the engine for the oil leak. I see what looks like a triangular shaped plate bolted on the back of each head. I think it may be leaking from both of these plates. The one on the passenger side leaking more than the drivers side. It's very difficult to get a good look back there.
Are there actually some type of plate on the back of each head?
Yes, there are 2 triangular cam shaft covers on the back of the heads. they are sealed with o-rings. It is likely that this is the problem. They are removeable to set the cam timing if the sprocket is removed.
Ah yes, the rear cam covers. Also not known as a high failure item, but if anybody messed with them for some reason and didn't replace the seals, a small leak would be likely. I think that is a way more probable cause of your leak than an actual head gasket problem.
Finding the seals by themselves might be a trick, though, because I don't recall seeing them listed anywhere except in a much larger engine gasket kit. You might inquire of a stealership; they often do have obscure stuff like that in stock and sometimes not even outrageously priced.
Kind makes me wonder, if they are not high failure rate items, why both would appear to be leaking. I can see where oil has dripped down both sides of the engine and it looks wet around them. But it's really hard to see back there with my light and mirror to know for sure. I don't see any signs that someone has done anything to them.
Even though the valve covers were recently replaced, I checked and there are no leaks that I can see from them.
Is there anything else in that general area that could be leaking?
There's failure and then there's failure. None of my 11+ year old cars on the lot (6 of em, all licensed and running) are completely free of oil leaks except for the '97 that had a complete short block rebuild and everything else cleaned, painted, and re-gasketed in 2006. Everything else leaks somewhere, and most in more than one place.
If my spouse's '07 Grand Marquis with 21,xxx on it starts leaking oil anytime soon, I'll call that a failure. Anything else on the other cars gets processed on a case by case basis. Sort of a triage thing. Is the leak big or small? Does whatever fluid that's leaking need to be replenished often enough to be a PITA? Does the location of the leak present a danger to the car or occupants? Does it leave evidence everywhere I go, and is it enough to be embarrassing? Etc., etc.
I can't think of anything else that might be leaking in your case. If the cam covers seem to be leaking more than you can tolerate, you might just verify that the bolts are tight first. A few things up top seem to get loose over time, especially things like valve cover bolts.
If you decide to replace the seals on those covers, the time to do it is at the same time as the intake gaskets. You gotta pull the plenum anyway, and then you can get that infernal plastic intake chamber that attaches to the throttle bodies out. That might give you reasonable access to the cam covers.
And while you're into it that far, you can check and replace inner tie rod bushings if needed, plus check the steering rack mounting bushings. Oh, and did I mention that would also be a great time to replace the heater hoses (if not all the hoses on the car) and the little 4" hose that "T"s to the back of the manifold?
But be careful listening to me.... I'll have you pulling the entire engine before you know it, and then you can *really* have some fun!
Ah, there you go. If the rack bushing job is queued up, then you really don't want to try that without pulling the plenum and the air chamber and stuff. So if you can get the cam cover o-rings (or maybe somebody who has an engine out of a car could tell you the size) then that's your opportunity to replace them.
And once you are in that far, you only have to pull the intake manifold to finish the gasket job and very likely resolve many driveability issues...
I degreased and scrubbed the engine down yesterday. I drove the car this morning and checked for oil leaks.
The block looked bone dry around the head gasket. The passenger side cam cover was pretty dry. I could see very slight seepage of oil around it, almost insignificant. The drivers side cam cover was a little wetter. I could see where oil has leaked out at the top, but it didn't look severe.
I could see where the oil pan meets the bell housing cover, that oil had dripped down. I doubt the cam covers could be leaking enough oil for what I am seeing. The oil pan gasket has been replaced. Maybe the rear crankshaft seal is leaking? I wonder why the shop wouldn't have noticed this when the transmission was out a couple of months ago. I had always seen oil leaking from where it is now, it's just gotten worse lately.
I think most of these cars by now probably are leaking from the rear main seal; two of my three are (not the one that got rebuilt in '06), but it doesn't seem to be too much other than a cosmetic issue. Both of the leakers are currently between 150,xxx and 155,xxx miles. One of them had its transmission rebuilt a couple of years ago, and only after the fact did I think about the rear seal. Since it was a transmission shop rather than a general garage that did the rebuild, I figured that's why that particular establishment didn't suggest getting the seal done at the time.
But once again, it's an issue that just doesn't seem to come up too often in this forum. Kind of like head gasket failures. Maybe it's one of those deals where something else is probably going to do a car in considerably before a leak at the back end of the engine will. Maybe a switch to "high mileage" oil and keeping an eye on things is sufficient in most cases? That's been my approach, anyway, and so far (knocking on wood furiously) so good.