Water pump

[H Suhling]

The old water pump on my truck started leaking and I replaced it with a new "improved flow" pump from NAPA. I run a 180 degree thermostat before changing pumps the heat gauge stayed on the 0 of the 160 with the 160 mark being between the 1 and the 6. I thought that would be about right with the 180 degree thermostat after changing pumps took about a sixty mile trip and the heat gauge went up to almost the 2 of the 212. I realize the outside temp was in the mid to upper 90's but I don't think it would make that much of a difference or would it.

Harvey

[Young Ed]

A new pump should not do that. It should make the opposite difference if anything but really it should stay the same. Did you change thermostats? Did you remove the old one and possibly put it in backwards? Perhaps your new pump is defective.

[H Suhling]

Everything else is the same. Only thing I changed was the pump. Don't believe the new pump would be bad but I guess stranger things have happened.

Harvey

[Young Ed]

Well what else changed? Was this trip significantly longer then previous ones? Was it significantly hotter outside then previous trips? If the answer is no to both of those then I'm thinking you are looking back at the pump as the only thing different. Only other thing I can come up with is disturbing the hoses maybe made one of them weak or just a fluke of timing that you've now got a bad hose thats collapsing. Maybe the new improved flow is too much for the hoses Have you rechecked your water level?

[H Suhling]

Ed

Hoses were all new at rebuild I even took the spring out of old bottom hose and put in new hose so it wouldn't collapse. Temperature was 95+ that and the new pump are the only difference. And I would think the temp would make that much difference.

Harvey

[Jerry Roberts]

It is a lot of extra work but you could put your old leaky pump back on for a test .

[HanksB3B]

If it's not the upside-down thermostat then what could it be, a belt slipping or less likely the impeller rotating free of the shaft and not turning inside the casting? Doesn't make sense, but anything is possible. After checking the belt and hoses, I think I'd install a new 180deg thermostat (couldn't hurt) before pulling the waterpump. If that doesn't work then I guess the pump is not working.

Puzzled,

Hank

[Dan Babb]

Is it possible that the new pump is a reverse rotation pump? I don't know if they even make pumps for these engines that go both ways...but I know for some engines (like the ford 5.0) they did make a standard & reverse rotation. Just throwing something else out there for you to check.

[HanksB3B]

the impeller was installed backwards?

Hank

[H Suhling]

Took a picture of my heat gauge today after a short run.

The needle is not that much past the 0 maybe I am worrying for nothing.

Thoughts?

Harvey

[Jerry Roberts]

If it's not the upside-down thermostat then what could it be, a belt slipping or less likely the impeller rotating free of the shaft and not turning inside the casting? Doesn't make sense, but anything is possible. After checking the belt and hoses, I think I'd install a new 180deg thermostat (couldn't hurt) before pulling the waterpump. If that doesn't work then I guess the pump is not working.

Puzzled,

Hank

I have read that there are some water pumps with the impeller reversed for engines that run backwards used in some boats . Looking at his photo of his temp gauge , it doesn't look too bad . It does run hotter than my engine though .

[H Suhling]

Thanks to all for the replies.

Harvey

[Phil Martin]

I wouldn't drive it that hot. Have a 50 dodge coronet now. Even with new radiator it ran hot. Put a 7 blade fan on it. All is good now.

[Dave72dt]

Take it out for a drive in the evening hours when temps are more what you are accustomed to driving in. You need to duplicate as near as possible driving conditions and situations to accurately compare temps. Still runs hotter,you have a faulty pump. Should run same or lower temp under same conditions.

[HanksB3B]

I have read that there are some water pumps with the impeller reversed for engines that run backwards used in some boats . Looking at his photo of his temp gauge , it doesn't look too bad . It does run hotter than my engine though .

Bet that's it.

Hank

[H Suhling]

Today I drained about a gallon of coolant from radiator to see if there was good flow after thermostat opened refilled with water. When I changed the water pump I topped off with straight antifreeze. When I went for a ride today the temperature gauge stayed where it normally does. Could an outside temperature 10 degree hotter and to strong an antifreeze mixture have been my problem all along.

Harvey

[HanksB3B]

but I have had wierd things happen like I'm at 212deg and start to panic and head for home only to have the temperature drop down to normal in a matter of minutes. This is a classic sign of a stuck thermostat. My guess is that somehow by draining some of the coolant you caused the thermostat to become un-stuck somhow. If this is an old thermostat I wouldn't hesitate to replace it with a new 180deg unit.

Hank

[Frank Elder]

Today I drained about a gallon of coolant from radiator to see if there was good flow after thermostat opened refilled with water. When I changed the water pump I topped off with straight antifreeze. When I went for a ride today the temperature gauge stayed where it normally does. Could an outside temperature 10 degree hotter and to strong an antifreeze mixture have been my problem all along.

Harvey

When you replaced the pump did you run the system with the cap off? You know to BURP all the air pockets out.....maybe when you drained the gallon it took air with it, hot air pockets have been known to be trapped in the system.

[H Suhling]

Sorry for the long post but trying to tell all I have done so far. Saturday I took the new water pump off:1. To see if gasket had slipped and covering block hole.

2. To make sure impeller wasn't turning on shaft.

3. Impeller not installed backwards.

While I had the pump off I took the heater hose that goes to the block off and hooked it to the garden hose and back flushed the block. No crud came out and had excellent flow. Reinstalled water pump and put in a 160 degree thermostat

instead of the 180. Took the truck to a show about a 35 mile trip. Running 50-55 mph the heat gauge read where the 180 read with old water pump. So all I know now is either the new pump causes the engine to run hotter or my heat gauge suddenly started to run 20 degrees + or - hotter than before.

Harvey

[bach4660]

the last thing to check would be the rad, after a run spray some water on it and see where it dries, maybe you have some blockage

[greg g]

So whats wrong with 180??? The temp rating of the stat is when it opens, not at what temp the engine will run at. The stat opening is when the flow goes out of the bypass loop and starts to circulate through the radiator insead of just through the engine.

[HanksB3B]

What qualifies the new Napa Waterpump as "improved flow". Just throwing this out there..Is the impeller configured the same as the original water pump? Just guessing it has a two blade impeller (different from the original) and maybe the two blade is not as efficient?

Hope I'm wrong,

Hank

P.S. Core exchange is something I totally reject. When possible, it's always best to save the original part even if it'll never be more than a paper weight. Ask me how I know.

Edited August 31, 2010 by HanksB3B

[H Suhling]

Hank

Here are pictures of my old pump the original pump had the two blade impeller

and here is a picture of an impeller like on the new improved pump

I would think the new impeller design would pump more water.

Greg

Nothing wrong with 180 degree thermostat in fact I would prefer to run a 180 instead of the 160 the problem is with new pump heat gauge reads almost 200 and with a 160 it reads 180.

bach4660

When I took the hose off the bottom of radiator the water column rose 6-8" it seems to be clear.

Harvey

[Dan Babb]

Maybe your current temp gauge isn't accurate. If you have one of those infrared temp gauges, take some surface temps on the block near the gauge sensor. The readings should be close so you can get an idea of your water temps.

Or for less than $20, buy a mechanical guage with a more accurate dial so you can get a better idea of your temp.

Something like this:

http://www.autozone.com/autozone/accessories/Sunpro-2-in-black-mechanical-water-oil-temperature-gauge/_/N-260f?counter=1&filterByKeyWord=sunpro&fromString=search&itemIdentifier=889867_0_0_

It's a bit of a mess to change the guage...when you pull out the old sensor, water will pour out. Make sure the engine is well cooled...hurts your hands if its too hot.

Also, did you say that with a 160, it was running closer to 180? If so, then being at 200 with a 180 probably makes sense. Maybe your radiator has some clogged runners, so it doesn't cool as well as it should.

[H Suhling]

Dan

Checking actual water temp is my next step probably should have already. The heat gauge has always been accurate up until I changed pumps. That's the part I don't understand. How can changing pumps affect the heat gauge causing it to start reading hotter than it should.

Harvey