Diesel engine vapor lock?

[myelo]

I would appreciate any thoughts on this. 2012 Chevy silverado 3500 diesel, about 180,000 miles. It's had two episodes that are very similar, one a year ago and one recently. After running about 30 minutes pulling a trailer (moderate but not heavy load), stopped for about 20 minutes. Then it started up but immediately died and would crank but not start. The first time it happened I tried a few things and eventually pumped the pump on the fuel filter and it started up and ran fine. So when it happened again recently, I did the same thing. It started up but died a few times and finally started up and did fine. Both times the outside temperature was pretty warm, about 90F. In between these two episodes, no problems.

I took it to the dealer after the first episode and they couldn't find any problems. I'm going to take it in again, but it's running fine now so I'm worried they might not find anything again. BTW, no check engine light came on.

It reminds of my 65 mustang back in the day would get "vapor lock" every now and then when it was hot. I never really understood exactly what that was and have no idea if that's even possible with engines these days. Air in the fuel line? Need new fuel filter? Fuel pump?

 

[grampamark]

Diesel fuel isn't volatile enough to vaporize in a fuel line. My guess would be that there is some contaminant or small, foreign object (the plastic seal from the top of a bottle of fuel additive, for example) which is riding around in your fuel tank and, randomly, gets picked up by the pump and blocks the suction screen at the bottom of the tank. When the flow stops, the blockage drifts away until next time.

I actually had this happen on an older Peterbilt truck about 15 years ago. Drove us nuts until we finally spotted the transparent little bugger on the bottom of the tank directly below the fuel filler opening where the light could catch it.

 

[day_trippr]

But this happens only when pulling a load in hot weather, stopping for coffee (or whatever) then trying to get going again.
It sure sounds like classic heat soak. Is it possible there's something blended in summer road diesel that could vaporize?

Cheers!

 

[OG-wan Kenobi]

Injection pump or waste gate solenoid are probably having a small intermittent issue but they should kick a check engine light if they stay bad. Your cooling system should be keeping your engine at operating temperatures so the weather is not likely the factor you need 2 things to keep that motor going fuel and air it's a diesel so that's where your problem is something is messing with one or both. I am sure you have been keeping up on your filters, very important on a diesel.

 

[myelo]

But this happens only when pulling a load in hot weather, stopping for coffee (or whatever) then trying to get going again.

Both times were after pulling a horse trailer with one horse. Unload the horse and then won't start. And both in warm weather. And both times were at the same place, 30 minutes from our house.

It's only twice so it could be total coincidence, but it just struck me that both times were so similar. And I've made plenty of trips in between, many much longer, with horses and no problems.

Thanks for all the ideas so far. I'll let you know if the mechanic finds anything.

 

[day_trippr]

Next time you go through that routine on a hot day, when you park to unload the horse, pop the hood up first. See what happens...

Cheers!

 

[grampamark]

I didn't read the OP carefully enough. I was thinking that the engine quit after 30 minutes, not that he stopped after 30 minutes. My bad.

It could be a faulty fuel solenoid. That might not throw a code because engine isn't running when the malfunction occurs.

There isn't a "summer" blend. There is No. 1 diesel, which is home heating oil, and No. 2 diesel which is what most diesel engines use except in very cold climates. No. 1 is lighter (less viscous) then No. 2 and is used in cold climates because it will remain liquid to a much lower temp. No. 2 diesel contains more suspended paraffin which will precipitate out and start to solidify at subzero temps, clogging filters or blocking fuel lines. No. 1 also contains fewer BTUs per gallon which reduces the power output of the engine. Winter fuel is either a blend of 1 and 2 or 2 with an additive to lower the pour point (the temp to which the fuel will remain liquid).

I have encountered a few diesel pickup owners who put No. 1 fuel in their vehicles on the assumption that the "No. 1" designation somehow means it's a higher grade fuel (it always costs more at the pump than No. 2). It just means that it has a lower SG than No. 2. It could be possible that No. 1 can vaporize under heat soaked conditions, though I’ve never experienced that or heard of it, for that matter (of course, there are a lot of things I’ve never heard of ).

 

[myelo]

Thanks for all the replies.

Turns out the fuel filter housing was leaking, allowing air into the fuel. They said cold fuel is more viscous than hot fuel so an early sign is it's hard to start when the engine is hot, compared to cold.

I have encountered a few diesel pickup owners who put No. 1 fuel in their vehicles on the assumption that the "No. 1" designation somehow means it's a higher grade fuel (it always costs more at the pump than No. 2). It just means that it has a lower SG than No. 2.

Not me. Given the choice in any fluid, I always go with the higher gravity.