The Cat 3126e, like all Cats, uses an external fuel water separator. Mine is no exception. In my case, since it’s an RV, that fuel filter is located right behind the radiator at the rear of the engine/RV. It is behind the grill but the grill isn’t removable. You have to crawl under the RV to access the damn thing. So, as it’s not a fun chore, I kept putting it off. Not just for months, but for years. I have read that many people change these filters once per year at the start of the season. I’ve never bothered to do that. Usually I’ll change it when there’s some other engine issue that needs maintenance or repair.
Anyway, my not getting ’round2it’ lead to this:
“Usually I’m traveling 55-60 MPH and it’s only a 6 hour drive to Winnemucca, but as I got closer to McDermitt OR, I couldn’t get the RV to move above 55, then 45, then 35, etc. And then the snow started getting thick. And by then I couldn’t get the RV above 25 MPH anyway. Definitely something wrong.”
Stopped for the night at an RV park, got online, and found a diesel shop in not very far away Winnemucca.
“Next morning, limped along under 45 MPH on the flats, I get there around 8:30 AM, Dave Schirrick Truck, met the owner as he was walking in the parking lot, explain the symptoms and he got me right in. And it was as we guessed, a fuel issue. There was water from the last diesel fill I’d gotten and it had worked it’s way back to the water separator. But the filter was years old and didn’t do a good job so some water had made it to the engines intakes. But this Cat engine, a 3126e, has a computer that senses the fuel was wrong and so had throttled back the RPMs to prevent damage. I hope. The shop replaced the fuel filter, did an oil change for me, and I was back on the road in around 3 hours. Feeling pretty happy about the fact that it wasn’t something more serious. A bit worried that by stupidly letting fuel filter replacement go by for years without changing it, I may have damaged the engine and it will show up later.”
But, the shop was excellent. Costly, but good.
The filter itself is behind that lower grill shown below, the bucket is nearly right under it. After it was changed, the mechanic had me do a road trip and after 10 miles on the road, I could tell that that had fixed the ‘limp’ mode issue and I was ready to go.
Here’s a shot of the shop property.
After returning, I had the tech change the oil for me. I had a new filter and 20 qts of synthetic oil in a basement compartment so we were all set.
While under there, I had him look for any hidden, extra fuel filters along the chassis frame rail that Freightliner or Winnebago might have installed. None found.
So that was it. Limp mode seems to have saved my engine from damage. I hope. I’ve put another 2,000 miles on it since and it runs great.