Serpentine Tensioner replacement

**KZOO3800** · 02-12-2013

'97 SE with 3800 Series II
Serpentine tensioner bearing seized, causing the plastic tensioner pulley to forcibly spin/melt off. Belt snapped shortly thereafter. Must replace the tensioner.

Does any part of this job involve removing power steering lines? Pictures of a typical replacement tensioner seem to suggest there are not only coolant passages but also power steering fluid passages. Thanks very much for your advice guys.

-Scott

A picture of a typical tensioner replacement part from Rockauto.com showing several fluid passages...

The pulley that spun off from my seized tensioner bearing.
IMAG0011_zps0e23b7ca.jpg

The other side of the pulley.

**mikedinthecity** · 02-12-2013

you can buy just the idler pulley, the bolt is backwards threads, meaning righty loosey lefty tight......should be like twenty bucks or so. if you do have to replace the whole tensioner assembly they are not cheap, no power steering lines but you have to remove the heater hoses, remove the alt, there is 1 plastic coolant elbow but you have to purchase the two pack.

**KZOO3800** · 02-12-2013

Thanks, I was hoping those were heater hose spots. Never had to unhook them so I was fearing the worst, however unlikely.

I'll have to go take a good look at the tensioner but I'm pretty sure I'm going to replace the whole unit just to be sure. Not just the pulley. The pulley bearing had been making enough "chirping/squealing" noises for the last few weeks that I thought my power steering pump was going out. Can't be sure what that means for the tensioner as a whole, but it looks ancient as is. lol. While i'm in there I may throw in a new water pump too.

I cut the engine within 30 seconds of the belt snapping and pushed the car into a nearby parking spot at my apt. complex.

**BillBoost37** · 02-12-2013

Once the alt is off. Three bolts, two coolant elbows, some coolant and you are home free.

**KZOO3800** · 02-16-2013

I got all my replacement parts but I have a few questions for those of you who have done the tensioner before I begin. I'd like to avoid draining the whole cooling system.

1. If I do this without draining my cooling system how much anti-freeze will come out of a properly filled 3800 SII at the elbows? A few cups isn't going to bother me. I've done a LIM job on this engine before but drained it completely before I did. The drain valve on my radiator is broken so my only option would be to pull the lower hose. Messy and I have no garage. Although I bought a 15 qt pan I'd really like to avoid pulling the lower hose if I can, I live in an apartment complex and will get fined for any messes.

2. Sealing the heater hoses/elbows into the new tensioner assembly: I bought RED rtv silicone. I've never detached these heater hoses before. I'd like to seal them up the best way possible. Exactly how should I go about doing this?

Again, thanks for your thoughts on this. It's been a long time since I had to wrench on this thing.
-Scott

**02NavyBlue** · 02-19-2013

Nobody answered, it may be too late already depending if you've done it already, but I just took the assembly off and reinstalled not too long ago.
1. I had to add a little over 3 quarts of antifreeze after removing the assembly. I just put a pan down and let it leak from the heater hoses and the ports in the engine where the assembly goes.
2. Be careful when removing the assembly, once the 3 15mm bolts are removed from the front of it, try to pull straight out and avoid pulling it sideways so that they will have smaller chances of breaking off. The upper one can sometimes fall into your intake manifold. The guy at NAPA told me to use a thin film of RTV around the orings before installing, I had the blue stuff and that worked just fine. The red stuff will probably work even better.
Pics:

**KZOO3800** · 02-20-2013

02Navyblue, you rock. Insightful advice and quality pictures. Thanks!

The day after my last post I drained all coolant without lifting the vehicle or spilling a drop... whew!
Quickly got to work removing the alternator and tensioner assembly from the engine. I didn't anticipate any trouble from that point. We all know how that goes...

Didn't see these little punks coming...

The heater hoses were fried onto their respective hose fittings. (the ones going to the heater core and back which need to be transferred to the new assembly). I hit them with WD40 and let them sit overnight. Popped the hoses off with vice grips and brought the tensioner inside with the hose fittings still attached to the tensioner. The metal heater hose fittings were all but welded into the bores of the assembly.

More WD40. I had to stand on the assembly and kick my vice grips with steel toes on to free the return-fitting. This didn't work with the send-fitting so I put the whole thing in my freezer for a day and hit the bore in question with a propane blowtorch before I pried the fitting out. Should go back together no problem but it's snowing intensely here so I may wait until tomorrow to finish this up.

**BillBoost37** · 02-20-2013

I've seen those fight, but not quite that bad. wow.

**PK2000GT** · 02-20-2013

To original poster...before your serpentine tensioner quit on you, did it make any louder than usual "whinning" noise when hitting the gas? Im just curious, because started making this noise yesterday.

**KZOO3800** · 02-20-2013

Every now and then id hear a chirping noise from the bearing if it was wet outside. The belt would squeak randomly too but always went away. I drove about 200 miles on the freeway and within a day of that it became extremely obvious something was going bad. It was more noticible at higher rpm.

**KZOO3800** · 02-21-2013

One last question concerning drive-belt size.
It's come to my attention that there are two common sizes: 93" and 93.5".
I'd been running a Dayco 93 inch for close to two years now. Wondering if that contributed to my problem/damaged my engine.
This time I bought both. Just need to know which one to install.

Also, with everything put back together the new tensioner pulley actually just barely touches my alternator without a belt on. Not sure what to make of this but I don't like it.

Just want to get this thing running again, really tired of not having a car. Thanks!

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