Do in-tank fuel pumps give any warning of impending failure/

Heres a tried and true method (our companies own experience) to prolong in tank fuel pumps life. We had a fleet of Workhorse chassis step vans. One in particular had a terrible record of faulty fuel pumps. Always at the same location. Even started to blame the driver for working with a local garage to split the cost of a new fuel pump and replacement. Finally figured out that this driver on a weekly basis would drive his van to the point of nearly empty so he could fill up at a buddys service station. Turns out the pump wouldn't get the cooling from the fuel in the tank and break down. Started insuring that all vans filled no less than a quarter tank and fuel pump problems went away.

I have read that SOME get weaker and weaker until they just can't pump enough fuel.

What percentage go out like that who knows?

But I do take a reading on the fuel rail valve stem thing to see if its getting weaker. Easier to change at my house than on the road IMO. Matter of fact, checking that is on my spring PM list which is coming up. Along with checking belts, hoses etc.

It's not a matter of "if" the pump will give out but "when" is the question. Maybe I'll be lucky and make the "where" more convenient, versus middle of nowhere.

Frequently you can hear the Ford fuel pump start squealing and get louder on its way to failure. Before it quits you entirely that is your clue to swap it out.

That is one place where GM outshines Fords. For a Ford fuel pump, one has to drop the tank or pull the bed.

As a rule that I use, based on a GM mechanics advice, I replace the pumps at 100,000 miles, and use only GM/Delco brand. They can be had for $120 and only take a couple of hours to change on a P/U truck -remove 6 bolts, unplug wire harness, slide bed back 3' and replace.

If you are dropping the fuel tank when a vehicle gets over 50k miles, might as well replace the pump for prophylactic reasons, although that will cost you about three C-notes for parts.

There is no way to tell when your motor will fail. Many say you can go by mileage, so if the average failure rate on a Sprinter Transmission is 110,000 - 125,000 miles, then you either decide to replace the older vans as they reach 100,000 miles, and still have some resale value, or plan on buying a $4,000 transmission for them in a few months.

Motors give little warning that they are about to die. Anything from your Air Conditioner to the fuel pump can fail the next 10 hours that you run it, or last another 10 years.

It would be expensive to replace a fuel pump motor every 50,000 miles when the average life is closer to 100,000 miles.

I have always heard that if you keep the pump underfuel, it will run cooler and last longer. SO keep 1/4 tank or more in the RV, and the pump will run cooler.

Fred.