I think I already know the answer but just wanted someone else to verify I am going to have to do the dreaded water pump change 1988 E150 with a 5.0 engine with 145k miles. I believe it may be the original pump.

Anyway the other morning when the temperature was in the 20's f, right after starting the engine I started hearing a noise similar to a belt or accessory bearing going out. The noise went away after the engine warmed up and has not occurred if the temperature is above freezing. I used a spray bottle with water and sprayed a little on the serpentine belt and nothing changed. I have a mechanics stethoscope but by the time I got the air box out of the way, the noise had gone away.

But with the air box out of the way I noticed what appeared to be a stain around the weep hole on the water pump. There was no puddled coolant and no smell though I do believe I may have smelled something a couple of times. There is also no coolant loss....

Yesterday I rented a pressure tester and pressurized the system to 20 lbs and there was no leak or pressure drop. Next i cranked the engine and let it warm up. The outside temps were in the mid 30's and the temperature didn't get past 190f on my gauge. I had the gauge/pump connected at first while the engine was running but the pressure kept going up and would have to bleed the pressure off every minute or so and I finally disconnected the pressure tester until the engine got up to 190f.
After the engine was up to temp I removed the radiator cap and reconnected the pressure tester and pumped the system back up to 20psi, still no leaks!

Okay well here is a couple of pics of the pump and weep hole. Sorry they are not so clear.
And any advice on removing the bolts would be welcome since I haven't broken any yet!

Thanks'
Anna

 

The impeller might be slipping on the pulley shaft causing your noise Annleigh. Get a helper to start the van while you immediately use your stethoscope checking for noise inside the water pump housing itself.

If the impeller is slipping there'll be no leaks etc----the seals would still be intact and able to hold pressure--you just might not be moving enough coolant.

Are you feeling for temperature rise in the larger radiator hoses when/if the thermostat opens?

 

I used to have these exact symtoms with my 1998 Opel Astra. It had a plastic impeller that would spin on the shaft.

Any overheating?

 

Thanks for the replies. No overheating at all. I have a mechanical gauge and keep a close eye on the temperature. The thermostat is a Motorcraft 192f and now that its winter them temperature hovers right around 190f. In the hot summer, the temperature was always around 192 to 195f. I also installed a NAPA heavy duty fan clutch about 3 years ago and it feels fine.
When I did listen with the stethoscope, the water pump sounded fairly quiet to me. The idler pulley had a slight sound to it and the secondary air injection pump has a very high pitched constant high pitched squeal sound to it that can only be heard with the stethoscope. I heard the air pump noise a couple of years ago then I wound up replacing the alternator. So I would say the pump sounds about the same..

No I haven't felt of the hose yet to see if the thermostat is opening but will.

 

You're running a serpentine belt, that little stain around your weep hole is nothing and you verified it's holding pressure even at operating temps...I would wait til its cold out again and the engine is cold. start it up, if it squeals, shut it off right away, Go to your belt tensioner use a can of WD40 or some other lubricant, make sure you have the spray straw and give it a couple of squirts on the backside of the pulley where the bearings would be and then restart the engine.
If you really think the water pump is on it's way out, you can check by opening the radiator cap after it's warmed up...pour a little pepper it the coolany, not much, just enough to see if it's pulled away quickly or if it kind of hangs there and moves back and forth...If it's the latter, then your impeller blades are probably word down...but you said it wasn't over heating so it's probably good.

 

Thanks Mike1! There is no overheating issue that I know of. The heater blows out good warm air at 140f, so the coolant appears to be circulating well through the heater core.
Just sitting in the yard, emergency brake on, in gear, and a little bit of throttle, its all I can do to get the temperature up to 190f when outside temps are in the 20's and 30's.

I think I will also pull the serpentine off of the crank pulley the next time it is in the 20's and making the noise. That way I can defiantly pin it down to an accessory and or eliminate anything in the engine or transmission.

I am curious as to why the stains are around the weep hole.

 

Watch the video

 

Take the belt off and spin everything by hand.

 

WEll, Mike1, that video makes me feel much better. Thank you! I have just never seen a water pump seep out a tiny amount of coolant till now.

Yes Muhford, I plan to rotate everything by hand as well as check the water pump for any play while the belt is off.

Right now it only does it when the outside temps are down in the mid 20'sF so I am just guessing that it is probably a old bearing that is dry or something worn that expands or contracts with the temperatures.

Last summer I changed the heater core because I had been smelling a very slight coolant smell occasionally. The heater core leak was very very slight and not enough to drip out the housing but I could smell it.. What I smell occasionally now, I haven't been able to pin point. Maybe I just worry to much with people talking bad about these old vans!
Mine has been good to me and so far I haven't been stranded away from home in 40k miles. That's part of the reason I try to keep up with the maintenance. Mot just routine maintenance but there are some parts like sensors with rubber diaphragms or moving parts, vacuum lines, rubber bushings, gaskets, ect that can go bad from age. My van may be a bit unique in that it is 33 years old with only 145k miles on it.

 

Well today it was a bit chilly and so i started the van and within a minute or so I could hear the noise. As soon the noise started I cut the engine off and removed the serpentine belt and restarted the engine.. WOW that engine is much quieter with the belt off... I checked the water pump and no play and it felt smooth as well as the AC, power steering, and alternator though I could hear a little bearing sound but I think that is normal. The smog pump turned almost a turn and would feel like it was slightly binding. I put the belt back on and when I started the engine, no odd sounds. I believe the is is something just starting to go out. I was hoping to catch it before it goes out away from home.. Maybe I just have to give it more time..
There is also a weep hole on the bottom of the pump and there is absolutely no sign of leakage down there.

 

Did you check the tensioner pulley? That's usually the culprit.

 

Yes I Mike. I replaced it when I replaced the belt abut 3 or 4 years ago and have only put 40k on the van since then. I used a mechanics stethoscope to listen to the pulley and though I could hear what I believe was the the bearing constantly rotating, there was no chirping or intermittent sounds.

Here is a good video about the tensioner and at 2 minutes into the video they start talking about belt wear and how it fits the pulleys.

I looked closely at all of the pulleys as well as the belt. everything looked good except for the new, not rebuilt NAPA alternator pulley. It appeared to show belt wear like described in the video. But is the belt is worn then that should show up on all of the pulleys shouldn't it? My guess is that it is just a cheap made pulley that was uneven from the factory. I don't know? There is less then 8k on the alternator.

Here you can see the wear lines or lack of wear lines on the pulley groves.

 

I'm betting your clutch fan isn't liking the cold. My chevy is doing the same thing on real cold mornings. If the temp is 40+ it doesn't do it. Even though it is newer it may be making noise on cold mornings from the slippage. Only good way to tell would be to take the fan off and just have the pulley bolted on there but then you also need a real cold morning to know if it worked.

 

it could very well be that alternator pulley.....if you zoom in on it, the 4 inside ribs look like they're chewed up.