Timing Belt Change Interval (time vs milage)

[MB_Electronics_944]

Hi, I'm new to the list.

I've owned my 1985/2 Guards Red 944 for about 8 years now.

I only average about 3,500 miles/year.

I changed the timing & balance-shaft belts in January of 1996 and since then have put about 20,000 miles on the car.

My question is this:

My timing belt is now over 5.5 years old yet only has 20,000 miles on it... how old can the timing belt get before it should be changed even if the 30,000 mile mark hasn't been reached?

The car has always been garaged so the rubber parts seem to deteriorate somewhat slower than on a car that is kept outside.

Any suggestions?

TIA

[Lawrence Coppari]

I don't think time matters much unless the belt has come in contact with oil. But to be on the safe side, I would change it. I have one vehicle that only has about 5K on it in about 5 years and am not changing its two timing belts any time soon. But there is a big difference between 5K and 20K.

[Bob's944]

My 11 yr old waterpump recently failed 11,000 miles ahead of schedule. I didn't have any reciprocal damage, ie. seisure and timing belt failure resulting in valve to piston collision. My belts were relatively new, we decided to replace the timing belt anyway and keep the balance shaft belt. The wear on your belts is going to depend alot on how it's tensioned, how hot it is where you live, how cold it get's if you drive in the winter, oil, dirt, sand... alot of things. I would inspect your belt and look for any signs of wear, cracking, teeth missing ect. Replace it if there is any signs at all of wear, it should look newish. The penalty of it breaking is too great a risk.

[Blackfoot]

it probably needs changing. if belts were made of metal, they would be fairly impervious to the elements, and you could pretty much just go by the mileage and do it every 30k, regardless of the time interval. but belts are rubber & fibre, and susceptable to deterioration from the environment.

[MB_Electronics_944]

Thanks for all the helpful information.

I decided to remove the T-Belt cover and have a look...

Here's a picture of the T-Belt after 5.5 years & 20,000 miles...

It still looks almost new!

[PrerYDoG]

Belts have to be done every 30k?

I thought it was 50k... If I have to do belts every 30K, that's WAY to much upkeep.

[TomH]

Lot's of different opinions on what the frequency of replacement should be. I've heard 30K, 45K, 50K.

I just replaced the original belts, rollers, cam seals and water pump in my car at 60K back in Feb. Mine's an auto, so I don't know if "hard" driving via manual shifts can shorten the belt lifespan or not.

As a daily driver, it looks like I'm going to put about 22K miles on my car per year, and will plan to replace the belts every 2-2.5 years. I just can't see doing it more frequently.

I'll plan to do just the belts next time, followed by belts, rollers, seals and pump 4-5 years from now. All of this dependent on how long I have my 944. Already thinking of my next P-car - 986 or 911