Was my timing belt installed wrong!?

subaru
forester

#1

So my husband and I just took our car in to get our timing belt replaced (before we had any problems… it hadn’t broken yet). We got it back from the shop and it was driving fine, but a few days later (had put about 50 miles on it), my husband went to take it to work and it just wasn’t accelerating properly (“misfiring”?) and making weird noises, so he took our other car to work. Oddly after scheduling the appointment to have it checked out, the car seemed to correct itself on the way to the shop. The repair guys said we now need new valves and spark plugs to the tune of about $500! I am a bit skeptical thinking that somehow these issues are connected. I am wondering if its likely that they did a poor installation on the timing belt and that then caused the problems with the valves and spark plugs (they said that oil got down inside the valve, and that was the problem) I dont know anything about cars (and unfortunately neither does my husband) but I just feel weird about this and want to know what you guys think…


#2

They are treating you like a mushroom…Keeping you in the dark and feeding you BS…

If you needed new valves it would cost $2000…Model year, Mileage? Have you ever replaced the spark plugs?

To sort this out, a skilled Subaru mechanic will have to remove the timing belt cover and check that the work was done properly. Then do a compression test to determine if the engine is mechanically sound. Then determine the cause of the misfire and fix it…Plugs and plug wires would be a good place to start…


#3

its a 2006 Subaru Forester… about 110,000 miles and we have never replaced the spark plugs so we were due for that (I wasn’t the first owner though, we got the car from a family member with 70K miles so spark plugs may have been replaced with that owner who did all the necessary maintenance) I guess my issue is knowing if there is any way to get them to admit if they may have done something wrong with the installation of the timing belt that caused our problems. So far they haven’t admitted doing anything wrong… they say the misfire was due to the oil in the valve or something seemingly unrelated to the timing belt (I HATE being so ignorant in all this!!)


#4

Without knowing the exact details it’s impossible to know what’s going on of whether the shop is at fault for anything or not.

It cannot be a cylinder head valve problem as 500 dollars would not touch a problem like that.
If the assumption, right or wrong, is made that the plug wells are full of oil and causing a misfire then that would not be anything the shop caused.

It could be that the 500 dollars is for new spark plugs and possibly new valve COVER gaskets; the latter of course being replaced to cure an oil shorted spark plug problem.

With some age and miles, any car with deep well spark plug holes can be prone to oil pooling inside the wells (or holes) and causing a misfire. This misfire can even be a present one minute, gone the next type of thing. Hope that helps.


#5

Thanks! That is actually really helpful! I guess it was the valve cover gaskets, not the valve… and it also helps to explain why the misfire was there one time and then gone later… i guess its just a strange and unfortunate coincidence maybe that it all happened right around the same time (and unfortunate for the bank account…) I appreciate your help. I am really just looking for peace of mind because I hate feeling like I might be screwed over because I dont know much about cars…


#6

Oil leaks into the spark plug wells are quite common with any make of car. Sometimes it creates problems and sometimes it does not. It’s all chance and a car may go it’s entire life running fine with oil saturated plug wires/boots.
Aged, high miles spark plugs can exacerbate the problem though. A spark that has difficulty jumping the plug gap inside a running engine will look for the next easiest way to ground and that is usually through an oil softened plug wire or coil boot into the cylinder head.

Quite often, this leak may not ever be detected until a misfire crops up or someone just happens to notice it during a routine spark plug service.


#7

too bad we cant change the thread title. turns out timing belt job was done right.


#8

Agree with ok4450.

I would simply replace the spark plugs, which should cost you less than $100 on a 4-cylinder engine. Yeah, the valve cover gaskets may be leaking a bit, but it may not be important enough to spend and additional $400 on.

Replace the spark plugs and move on. If oil leakage through the valve cover gaskets continues to be a problem, you can always replace the gaskets later.


#9

If you need new valves, they screwed up. The head would have to be removed and the only way valves crash is if the timing belt slips or breaks. You are do for plugs and wires. You might as well do the valve cover seals while your there. That would cost $500. Valves $1500 at least.


#10

If you’re following your factory maintenance schedule, you were due for spark plugs at 90,000mi (every 30,000 for NA Subarus). I’m wondering why you were asking us if it was misfiring, as that comes up as a specific CEL code (P0301-P0304) so the mechanic would have told you for certain. Also, your mechanic should not just replace the gaskets without evidence of an actual leak or oily spark plugs. Yes, they do go pretty readily, but there is no specific maintenance interval on them. Oil on the valve covers or heads mean new valve cover gaskets, oily spark plugs mean new spark plug guide gaskets, but since they’re cheap and right next to each other, if you replace one you replace them all. If there’s no oil leaking, and the spark plugs and wires don’t fix the misfire, next up would be the coil pack. The mating surface for the coil pack should be cleaned; it used as the ground.


#11

If you’re following your factory maintenance schedule, you were due for spark plugs at 90,000mi (every 30,000 for NA Subarus). I’m wondering why you were asking us if it was misfiring, as that comes up as a specific CEL code (P0301-P0304) so the mechanic would have told you for certain. Also, your mechanic should not just replace the gaskets without evidence of an actual leak or oily spark plugs. Yes, they do go pretty readily, but there is no specific maintenance interval on them. Oil on the valve covers or heads mean new valve cover gaskets, oily spark plugs mean new spark plug guide gaskets, but since they’re cheap and right next to each other, if you replace one you replace them all. If there’s no oil leaking, and the spark plugs and wires don’t fix the misfire, next up would be the coil pack. The mating surface for the coil pack should be cleaned; it used as the ground.


#12

I have not been able to get on here recently, but I hope this post helps! I replaced the timing belt in my 1999 Forester after the sprocket idler gear broke and tore up the belt. I did everything by the book and replaced the gear set, too; however, it had misfire problems and a clicking noise that I could not figure out and so I took it back apart and dbl checked everything to no avail. The misfire was very bad at idle, too. However, at speeds above idle (say 20mph) the miss disappeared and there was no loss of power nor oil consumption. I finally chalked it up to a burnt valve. three months later we took the Subaru to the Smoky Mtns and on the way, the clicking noise got louder and louder to the point I though it was a rod bearing! However, no smoke, no loss of power, nothing. We drove the entire trip that way. (People would stare it was so loud.) I stopped at an Autozone and the guy put it on the analyzer which said all was ok but a misfire on #4…he advised it sounded like the air conditioner compressor was going out! When I got it home after driving it for all this time and just getting back from a 800 mile trip, I was able to check it out thoroughly. I took it back apart and guess what? The new Dayco tensioner idler pulley that I’d installed was defective!
The gear was jumping up and down like mad and there was inadequate tension on the belt! That caused the misfire at idle and the noise was it slapping against the top of the engine where it was installed. I put a new one in and the Forester runs like the day I bought it! Like new! No misfire, no noise! Fantastic! (I have 245,000 miles on it and it uses no oil has plenty of power, too!)


#13

For next time, tell the mechanic that you don’t know a thing about cars so would he please give you his diagnosis and recommendations in writing. You can say that you want your nephew, neighbor or other person who understands cars to review things so you can decide if you want to sell the car and get another or for whatever reason you can think of that sounds good. You do not want the mechanic to think that you don’t trust him, it’s that you may not trust your own memory.

No estimate, contract, or promise is good unless it is in writing.

This action should result in a tendency for a mechanic to think twice before he decides to cheat an unknowing vehicle owner. It also results in removing potential communication errors regarding your ability to understand and recall. If a mechanic refuses to provide an assessment and repair cost estimate in writing, then move on to another who will do what you, the customer, want.


#14

The idler pulley spring is only to set the initial tension on the belt. You are supposed to bolt down the pulley so that it cannot move once the belt is tensioned. The spring is no longer part of the system once the pulley is bolted down.


#15

I should also mention that you do not need to ask the mechanic to provide you with documentation that describes his assessment of what is wrong and what it takes to correct it. You can bring paper and pen to make your own notes of what the mechanic is telling you. You don’t need to ask for a signature from him; just make sure that he agrees with what you wrote. This also will make him think about the accuracy of his diagnosis and fairness of his cost estimate.

I’d like to add that I have changed timing belts on my VW many times; have never had a toothed timing belt skip a tooth even though I run my belt a little loose when cold to compensate for thermal expansion of the engine block and head which tightens the belt. A timing belt, in my view, may skip a tooth if it is set extremely loose or is deteriorated due to age. I have found that it is easy to install new a timing belt in error by one tooth quite easily if I am in a hurry.


#16

I am under the impression that he did this himself.


#17

Ollie,

Is your engine an interference engine? If so, maybe you bent a valve?


#18

I bought my used 2000 Corolla CE a couple of months ago which had 45k miles. Now, it has about 50K miles.

Since the car is 13 years old, should I change the timing chain and tensioner or just do it at around 80k miles?


#19

@xaml

Timing chains don’t have a set replacement interval

They can’t just snap like a timing belt

Keep driving

If it ever stretches so much that there is a problem, it may very well start rattling


#20

@db4690 Timing chains eventually fail but they will start rattling long before that. I have only ever replaced on and that was on a 1984 Chevy Impala V8 with about 250,000 miles on it. It developed a rattle like a diesel and my mechanic, who had replaced a few, immediately identified it and said it would probably run for a year like that before it snapped.

He replaced it with a double sprocket/chain set that would last the life of the car. The original Chevy set was a cheap plastic pair of gears.