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Timing Belt Covers: Hermetically Sealed?

I have a 1994 Mazda Protege, 4 door, tan, with 203,000 miles. Recently I had a new timing belt/water pump installed. Afterwards, a friend of mine looked at the work and said he could see the timing belt in some places. There are gaps in the cover from maybe a hairline to 1/8" wide.

I suspect the gaps were there for awhile when a previous garage installed a timing belt years ago. My friend told me that there should be absolutely no gaps, so I went back to the garage and fussed about how there should be no gaps. The garage is now ordering an upper and lower case for that area to replace the current cases, which apparently are warped and worn. The mechanic I talked to said this wasn’t an issue really, that a lot of cars have these gaps.

My question: Who is right, the mechanic or my friend? Do the cases have to completely seal off the timing belt from the elements, or is it okay if there is some daylight in some places? For peace of mind, I have ordered the new cases to be installed, but am not sure if I am being taken for a ride by either the mechanic or my friend.

Not an issue. Some folks even take off the covers to give the engine a more mechanical look. I don’t recommend that, but your friend is worrying too much.

I agree that this is not an issue. And, I personally wouldn’t spend that money on a 14-15 year old car. But–to each his own.

In all fairness, your friend might not know that much about cars with timing belts. Cars with timing chains typically do get oiled, and that would be a scenario where you’d need the timing hardware sealed up.

I’m a little more confused by the last post talking about some timing belts being sealed in and lubricated by oil. I replaced the timing belt because the mechanic said there was an oil leak nearby and if I fixed that leak and should replace the timing belt because it would be covered in oil and that wouldn’t be good.

Is it a different type of oil in a sealed unit? The timing belt definitely is under a cover.

mr_josh is talking about a timing chain which some cars have instead of a timing belt. Your car has a timing belt so yours is not lubricated by oil. In fact, the reason your mechanic told you to replace it after fixing the leak is because the oil will speed the deterioration of the belt. An engine with a timing chain has an actual metal chain similar to a bicycle chain but larger and stronger instead of the rubber belt.

Reread mr josh’s post.

He’s talking about a timing CHAIN…NOT a belt. Chains NEED oil…belts DON’T.

Thanks for setting me straight. The more I learn, the more I believe I should let things stand as they are, as previously posters have noted. Odds are very slim that something catastrophic will get through a 1/8" gap and hurt the belt.