II have the day off, so what more fun can a mechanic (wantabe) do then installing a back flush kit and flushing the engine.......


In the process of doing it, I noticed that the top radiator hose had basically no pressure. The engine stayed cool (although it was only 760 degrees out), so it looks like I've got a failing water pump.

I've gone to autozone and got the procedures for putting in a new pump into my 3.3L engine. Also, I got the procedures for replacing the serpentine belt. However, the procedure seems to not be to clear. Specifically it says:


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All of the belt driven accessories on the 3.3L and 3.8L engines are driven by a single serpentine belt. The belt tension is maintained by am automatic tensioner.

Raise the front of the vehicle and safely support it with jackstands.
Remove the right front splash shield.
Release tension by rotating the tensioner clockwise.
Remove the belt and install a replacement.
Proper belt tension is maintain by the dynamic tension.
Install the right front splash shield. Lower the front of the vehicle.
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My questions are:

1.) It tells me how to "release the tension" but not how to tighten it? In looking at the forum some people talk about putting in a wedge of wood, but I'm not quite sure what there talking about??

2.) Also, I the procedure says to "Release tension by rotating the tensioner clockwise". Do I use a wrench on the bolt on the belt tensioner?

Any help would be greatly appreciated.



Best Regards,
Stan

Correct, you release the tension by turning the center tensioner pulley bolt clockwise.
I am guessing some peeps use a wedge to hold the tensioner in the full clockwise (un-tensioned) position, to make installation of the serpentine belt easier.
Once the belt is in position, releasing the tensioner bolt causes the spring to return to the tensioned position. It is thus, an automatic belt tensioner.

Don't know how it is on a 95 but, on a 96 there is precious little clearance between the fender well and the tensioner bolt. I had to grind down a socket (15MM I think) to get it and a breaker bar to fit in there. I have since bought a kit Sears sells that works great. Consists of a long thin metal bar and low clearance sockets you can attach to it. Think it was around $30.

I second webbee's description.

What RIP described is a "serpentine belt wrench", a handy device to have when you have a serpentine belt with dynamic tensioner. I got one and it works great. You could use a 15mm box end wrench if you are REALLY STRONG or can find one that is at least 3 feet long.

The dynamic tensioner is spring-loaded and pivots on an axis about two inches off the center line of the pulley. When you put a wrench on the center bolt for the pulley and turn clockwise (tighten), you work against the spring force of the tensioner and loosen the belt, allowing you to remove the belt. Once the belt is clear of the tensioner pulley, you can release pressure on the wrench, allowing the tensioner pulley to pivot with spring force back in a counter-clockwise direction until it stops. Do this slowly to avoid injury. Now you can work on the water pump and any other accessory that is belt driven. When you go to reinstall the belt, the belt won't go back over the tensioner pulley until you once again rotate it clockwise with a wrench. Once you get the right tools and play with it a bit, you will understand completely.

Now, if the bearing in the pulley on the tensioner starts to make noise, you can replace the pulley and bearing without removing the tensioner. Just remove the belt first and loosen the center bolt on the pulley by turning it counter-clockwise. The pulley will come right off. The replacement pulley for this is identical to the idler pulley. The replacement of both of these pulleys is easy insurance when you have the belt off.

I have learned first-hand that the tension spring in the tensioner can get weak over time, without failing completely. A symptom of a weak tensioner spring is a rattling noise that you hear only when the engine is idling in gear and louder when the A/C is on. The tensioner is held on by a single bolt, but it is located on the back side of the engine. It is very hard to get to and damn near impossible to see if you have an AWD PTU hanging off the right side of the transmission, like I do. When I replaced my tensioner, I bought my own at the auto parts store and paid the local dealer $188 (2 hours labor) to do it for me. Best money I ever spent.

Regarding your water pump, the only reason you should ever replace it is if the shaft seal is leaking or the bearing is making noise, or loose or all three. The pump is held in the external housing with 5 bolts. Just release the belt, drain the coolant and unbolt the old pump. Reassembly is just the reverse.

Let us know if you have any questions or comments.

Oh, one more thing regarding your backflush diagnosis. Most backflush kits I have seen are hose connections installed on a heater hose. If you are adding fresh water (cold) to your cooling system through a heater hose, even if the engine is running, your thermostat will stay CLOSED. This forces the water out of the block through the lower radiator hose, up through the radiator core (the backflush) and out the top of the capless radiator. You will not develop any pressure in the upper hose. In fact, there will be no water flow in the upper hose, either, due to the closed thermostat. What you described is NOT indicative of a bad water pump, or at least I don't think it is. If anybody disagrees, please let me know.

GAD ZOOKS!!! I've got to agree with KManiac. Your pump is fine. Guess I should have read closer. With the t-stat closed you won't have any flow in the upper hose. To make sure configure everything back to normal and let the van idle for 20 minutes and watch the temp gauge.

Kmaniac, RIP and Webbe,
Great advice and suggestions! Concerning the water pump, I had the engine on for 30+ minutes (without the water hose) and drove it to the car parts store as well (about a one way 10 minute drive). I kept on checking the hose and while it was very hot, it never developed any pressure. In looking at my Hanes manual, they said that was indicative of a bad water pump.

The temperature of the engine always stayed normal though.

Does it sound like a water pump that’s starting to go bad???


Thanks,
Stan

If the temperature gauge is in the normal range and you're not seeing any boil over then I wouldn't worry about it.

The device on your cooling system that regulates cooling system pressure is the radiator cap. If you drive with the cap off, you won't have any pressure on the system. If the cap is on, but is is bad and not holding pressure, you won't have any pressure in the system. When the cap in on and the engine is warm, cooling system pressure will be uniform throughout the system. You will still be able to squeeze the hoses whether regardless of cooling system pressure with a correctly functioning radiator cap. The hoses will not become as stiff as an inflated tire when the cooling system is at operating temperature. Sounds to me like your cooling system is functioning correctly. When the engine is warm and you carefully try to remove the radiator cap, is pressure released? If so, no problem. If not, replace the radiator cap.

KManic and RIP,
We'll either the problem is solved--or it was all operator error in the first place......

What I did:

I tried moving over the radiator cap from my 2002 Grand Voyager and that didn't make the hose hard..... Then I followed a friends advice and put in a new thermostat and that didn't make the hose hard.......

But then I tried squeezing the radiator hose on my 2002 Grand Voyager (with both of the radiator caps) and was shocked to see that it felt the same as my 1995 Grand Caravan! In other words, had been squeezing my Olds and Ford hoses and thought that they all should be rock hard. On the Chrysler's, they are apparently not rock hard.


I'm not sure if the new thermostat did anything or not--but it was only $8.


Thanks again for all your help.

Best Regards,
Stan

You da' man, Stan! We all learn something new everyday. Glad to help.

Good to see you followed through and figured it out. Another mystery of life is solved.