I have had a problem with my car idle hunting for about the past year. Last week my car threw a code and my code checker said that all 4 cylinders were misfiring. So I am still under warranty and took the car to the dealer. They said the intake manifold was leaking. Two questions come to mind: Has to engine suffered any damage from leaking for over a year? and Do they automatically change the oil when changing out the intake manifold/gasket?
I did have an oil analysis last year (5/11) through Blackstone Labs and no antifreeze was present in the oil but the silicates were mildly high. Car is a 2005 toyota corolla with 102,xxx miles. The dealer also did the head gasket and a couple other engine gaskets 1 year ago.
I don’t think this has a heated manifold. No coolant in there.
When they said it was leaking they must have meant a vacuum leak, which can cause misfires on all cylinders…
It’s unlikely that any permanent damaged has occurred from running with the vacuum leak for the past year, but there are circumstances wherein it could. Lean operation can cause hot operation, much like using a bellows on a fireplace. And certainly it can cause inability of the system to maintain a good air:fuel ratio, which can manifest itself as other problems such as carbon despoition on the upstream O2 sensor and converter catalyst. And the valves,
A shop could want to change the oil out of concern for possible excess fuel caused by the difficulty with maintaining metering. Excess fuel could possibly wash down the cylinders. This seems a stretch to me, but I’ll never fault a tech for playing it safe.
I picked the car up and the service writer said the leak was strictly vacuum. Thus no need to change the oil. I had it changed the next day anyway because it was almost due and I had a coupon. In the winter I just don’t change my oil myself. Thanks for all the great tips!
I’m a bit late to this discussion but there are a few oddities here. You say the dealer did the head gasket and a few other gaskets about a year ago so this adds a few things to the mix.
That would include whether the cylinder head was surfaced and if so this means the intake would have been removed. If this head gasket failed due to overheating I’d say someone was lax if they did not check the cylinder head for flatness and the same goes for the intake manifold flange.
You’ve had idle problems for apparently the same length of time since the head gasket was replaced and to trigger misfires on 4 cylinders means the intake would have to be horribly warped
Offhand, it seems to me that someone dropped the ball while doing these repairs a year ago. Did they charge you for this latest gasket replacement?
The car has idled when cold since I bought it. I bought it in September of 10 so here in Wisconsin it wasn’t cold enough yet. Around November or so I noticed that it was idle hunting. In January I had a coupon for an oil change at another dealer across town and they notice that the timing chain tensioner was leaking. I took it to the dealer that I bought it to. To avoid a diagnosis fee I brought up the idle hunting while they were checking the warranty work out. They came back and said that the throttle body was dirty and they wanted a hundred bucks to clean it. I told them I’d rather get messy and do it myself. They said that yes the timing chain tensioner was leaking and a few other gaskets were on the verge of leaking.
Here is the repairs listed in the service records:
R&R FRT TIMING COVER ASSY, RESEAL FRT COVER,REPLACE FRT CRANK SEAL, REPLACED TIM ~|~C/S TIMING CHAIN TENSIONER LEAKS OIL ~|~ ~|~93394 RESEAL FRT TIMING COVER, CRANK SHAFT SEAL, TENSIONER O RING, VALVE COVER GASKET
Here is the parts list:
FIPG OIL PAN 0029500103 1
GASKET, CYLINDER HEA 112130D040 1
SUPER LONG LIFE COOL 00272SLLC2 1
RING, O 9030122013 1
SEAL, TYPE T OIL 9008031049 1
I get a chuckle that they say that they replaced the valve cover gasket but it is not in the parts list. I also noticed a head gasket and gallon of coolant listed in the parts list but not on the the service records. I assume they changed it because of the gasket and a jug of coolant in the parts list.
This fall the car was still idle hunting and it was getting really bad so I did take it into a garage because they only charged me 30 dollars and it was worth sparing a few of my fastly depleting brain cells. I still had idle hunting problems and then one day the CEL came on and I checked the code and all 4 cylinders were misfiring. I didn’t notice the motor running that rough but we took it in right away.
It’s impossible for me to really figure out what’s going on here but I do have a very hard time seeing an intake manifold being bad enough to cause a misfire code on all cylinders. About the only way I could see this happening would be if the head gasket was faulty because of severe engine overheating which could then warp the flange surfaces.
I’ve done a lot of head gasket repairs but have never seen an intake warped that badly though.
A dirty throttle body, which includes the Idle Air Control valve, can certainly cause idle problems.
I certainly won’t accuse the shop of wrong doing based on the little knowledge I have of the actual diagnosis and repair but it does sound a bit odd and just offhand, might smack of someone guessing at things.
It’s kind of strange that your Toyota would be suffering from multiple oil leaks, head gasket, and intake gasket problems. That’s way out of the norm unless the car had a shaky history before you bought it. Hopefully it’s all ironed out now.
I don’t think they replaced the head gasket. I think they pulled a head gasket kit to get the seals they needed to reinstall the timing cover and valve cover properly. The head gasket kit would include all of those seals to do the job, and probably cost cheaper than each of those seals independently. Last time I did a head gasket, the kit included everything but the oil pan seal, front crank seal, and rear main seal.
And the coolant was probably removed to get the timing cover off. I cannot remember if this engine had the water pump on the timing cover or not, but changing the coolant makes sense, since it has to be drained.
I am amazed that you still have a warranty on a 7 year old car with over 100,000 miles on it. You, sir, are a lucky man.
As far as damage, if the CEL only popped on just this last week, there is no appreciable damage. The ECU most likely compensated for the leak by squirting more fuel, preventing the engine from running lean. This works until the ECU fuel adjustment reaches a preset threshold. Then, it sets the code. I’m kinda surprised it didn’t set the P0171 code for system too lean. This is the code I got with the intake manifold leaking on my Ford Explorer. It would stumble and shudder on cold mornings for a minute or two, but didn’t throw a miss-fire code.
I know the guy that traded this car in was in his early 60’s and still drove quite a bit. I have service records that shows that he drove around 18-20k a year. He never had any major service done. When I got the car its had these couple of problems but nothing terrible. Now the clutch has begun to slip just a tad on the freeway but it also has 103,000 miles on it. I have a warranty for another 20 months. Very grateful for that.
Clutches are considered a wear item and not a warrantable one so I wouldn’t count on getting that done for free.
As to the original problems (oil leaks, head gasket, intake leak, etc) I’m afraid that I just flat have no idea what the deal is on this car.
If the car were aged quite a bit then I could understand multiple oil leaks and whatnot but an '05 with only a 100k miles should not be suffering these kinds of problems unless it was just flat abused due to overheating.
While I don’t know the minutae behind the diangosis and repair of these problems I get the feeling there’s been some misdiagnosis and possibly some unneeded parts changing going on. That’s just a nagging feeling with no real evidence to back up that feeling though.
This car has a plastic intake manifold. The manifold gasket was changed in later 2005.
Manifold vacuum leaks are a common problem in the 2003-5 models.
Timing chain tensioner o-ring oil leaks are also a common problem. Something I take a look at twice a year when I change oil on my 2006 Matrix.
Thanks for all the great info. I do know that clutches are a wear and tear item. I am going to ride it out until spring so I can change it myself but if it gets too bad I will probably bite the bullet and have a shop do it. I have never overheated the car myself. As for the old owner I am not sure but I do have all the service records as he had the car serviced only at the dealer and he did all the fsm on it and none of the records ever indicate any problems besides a flat tires and burnt out bulbs. So i have no idea how he drove the car. Would be nice to know though.
But again thanks for all the help and the very informative replies