I put a new water pump on my 92 explorer less then 10,000 miles ago. It was OK at that time. Now it runs much hotter then it ever used to, getting up to around 240 on mountain grades. I changed out the thermostat, hoses, and anti-freeze but it still is running hotter then it ever did before. Radiator has no leaks, has always had the antifreeze maintained so I'm pretty sure there is no plugging on the rad. Engine runs very smoothly with no evidence of any head gasket problems.
How many of you have ever seen the impeller of a water pump be the cause of this? Since I can't find anything else I'm thinking of changing the wp again.
I'd assume that given that neither the old impeller nor cooling system in general was fouled, the "new" one wouldn't be too An overheating condition isn't usually a fault related to a WP. I have only once in more than 50 years witnessed a metal impeller coming loose from a shaft and would accordingly consider that quite rare. However I was recently informed that a "plastic" impeller on a newish VW bug pump came loose or otherwise failed (resulting in a long, lengthy and costly repair), so there's always that possibility too (I have neither needed to nor made my living wrenching in decades).
From THAT description?! What an absolute steaming pile of the most putrid conceivable brand of horseshit (you'll note the telling thorough lack of even so much as an attempt at an explanation as to any type of failure mode). But then again that respondent is well known for his total BS offerings.
I have never seen a bad impeller nor have heard directly from anyone that has. I have heard rumors that some impellers are designed to run the other direction but have never seen one or know of anyone that has. One pump fits many engines but use different gaskets. My guess is its something else. I would start with a new radiator.
Yes there exist many usually non-interchangeable (with standard) reverse rotation water pumps for vehicles, but no Fords that I've ever run across or am aware of.
It's far more common that it used to be. Especially with re-man pumps.
Did it start running hotter suddenly or has it been creeping up? Check the fan clutch yet? Radiator clean through the fins, A/C condenser clean? Have you checked to see if that is REALLY the operating temp. using a mechanical gauge? Could be a sender going bad.
If you haven't seen a reverse rotation pump you haven't worked on anything with a serpentine belt. There is an easy way to tell if the pump is normal or reverse rotation. Simply look at the drive belt. If it drives off the ribbed side of the belt it is standard rotation. If it drives on the back/flat side of the belt it is reverse rotation.
There are a LOT of common engines that use R/R pumps. I don't know of a single maker that didn't have engines that used both directions based on the year and option package.
Check and see if the radiator is covered with debris. I tracked down a cooling issue to the radiator, no leaks, I had maintained everything properly, but it just wasn't doing the job. Given the high milage I figured I'd just replace it since I could get a deal on a upgraded unit from ford racing. When I went to put it in I found the main portion of the radiator, that I couldn't see because of the AC heat exchanger (between it and the radiator), was almost entirely blocked with debris. I swapped it out anyway. On another car of the same model I just cleaned off the debris and the problem went away.
On another note, if all else fails might want to check the catalyst and see if it's becomming plugged.
I've seen impellers that been eaten away ( not in 10k though), impellers that have broken loose from the w/p shaft, impellers installed wrong on the w/p. It is possible you have a defective pump.
Also double check you have the serp belt routed properly in case the water pump is running backwards.
I have seen lots and lots of BMW pumps with plastic and diecast impellers that crack and spew out fragments that get stuck in the block. Lots of fun.
I have seen two otherwise-identical-looking GM pumps that had impellers designed to turn in the opposite directions. Just fine until the guy at the dealer accidentally puts them on the wrong shelves.
But I have mostly seen fraudulent rebuilds.
I would not replace anything without testing it first. A garden hose is your friend. Find out how much water is going through each part of the system and why.
I see you've got plenty of replies, but my first thought (from my knowledge of Chevys which may not be directly applicable) is that is the engine in your vehicle available in both V-belt and serpentine belt configurations, depending on year/model? If you replace a "reverse rotation" pump with one from a conventional v-belt model or vice versa, the WP will be a lot less efficient.
I've never seen a bad impeller personally, but it is possible, especially with the newer composite/plastic impellers. BMW has had some issues with this in the past few years.
Another potential issue with rebuilds I've seen was an impeller pressed too far onto the shaft causing excessive clearance between the impeller vanes and the housing when installed. This was a known issue with some rebuilt pumps for Studebaker V-8s a few years back. One vendor was hand checking the pumps and using a gear puller to tweak the impellers to the correct position before shipping them out.
Long story short, I would personally test the thermostat with a saucepan and a thermometer; next check and make sure that the lower hose (assuming conventional flow) isn't collapsing. If neither of those indicate a problem and the rise in temp. coincided exactly with the maintenance items you listed, occam's razor suggests trying a new WP.
Ah, I didn't think of that. Add to the list of things to check that if the vehicle has an electric fan that the connector didn't become dislodged when changing the WP and hoses. Likewise with the thermoswitch in the radiator controlling same, if there is one. (sometimes it's in the rad, sometimes it's elsewhere - I don't know F*rds.)
Easy to verify that the fan is working at least, just turn on the A/C.
99.44% of cars with an electric fan and A/C will run the fan at all times when the A/C is on.
I suspect I got it at autozone or ORielly. I'm going to find out before redoing it and then go elsewhere.
I did check the sensor with an infrared temp gun and it's running hot. On the trip in the mountains it got hot enough that the PCM shut down the AC at what looked to be about 240 degrees. When it cooled down to around 230 the AC came back on.
Engine driven and supposedly once you are over 40 mph you don't even need the fan and it got hot at speed. Don't see anything blocking but I'll look again. Fluid fan passes the "spin" test.
I've been wondering about the RRotation thing but I drove the truck almost 4000 miles across the US during the summer and it wasn't having this problem. Then after I was home for a few weeks I drove it up and back to the Grand Canyon and it was close to overheating the whole time. Of the things I can see, the radiator, fan, belt, nothing looks bad. Engine runs smooth as glass, same gas mileage as always, same power (or lack thereof), no engine check light. So I'm thinking of things I can't see, like the impeller.
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