Losing Fuel Coolant - No Obvious Leaks - Diesel Forum

JohnD333 · 08-05-2009, 10:40 AM

I had cab off and valve covers off 1,500 miles ago to test fuel pressure and ended up with a replaced high pressure fuel pump. Prior tothat I had been running with Ford's computer monitor in place for 500 miles to track a power loss/stumbling problem. The regular pump was replaced 8k miles ago. I am now losing fuel coolant someplace and there are no obvious leaks. I have 26k miles on Job 1 450 w/4.3 gears and did have engine coolant radiator replaced once but never had variation in fuel coolant before, and truck use (pulling 14k 5th wheel camper) is the same as always. Since that repair 1,500 miles ago I have added coolant 3 times to resevoir when stone cold, adding to middle of window where it has always been. I have also regened every 80-120 miles during this 1,500 mile trip evenwith flate 60 mph for hours on end, with usual 9.0 mpg, adding about 1.5 qts of fuel to the oil as "usual" as well. Each evening and next morning fuel coolant is below the window requiring 1/2 to full cup to replenish to middle mark of window in the AM. Temps are in 80's day and night here in MA; were up to 105 in daytime in SC. No temp or power issues when driving here.

2,000 miles earlier I had engine pulled for replacement of many leakng oil seals. PS, some are leaking again.

Any suggetions on what/where to look would be appreciated. Dealer can't get me in for a week.

Thanks in advance,

John

rlchv70 · 08-05-2009, 10:50 AM

This cooler also cools the turbo actuator. Look in the Vee of the engine for signs of coolant residue. The coolant could leak there, but dry up due to the heat of the engine.

JohnD333 · 08-06-2009, 06:35 PM

Richv70, nice and clean from being torn apart just 1500 miles ago, except very dirty (yes just like the engine after 1500 miles) engine oil 1/4 fills the the 1.25(?) inch bore cap that sits in that v to the drivers side of the fuel filter.

rlchv70 · 08-07-2009, 11:16 AM

You sure it's oil? The coolant could get discolored with soot and look like oil.

Anyway, you could get a coolant pressure tester. It should help identify where it is leaking from.