I hear that, one bad fill-up out in the middle of nowhere and youre SOL. Ive been in that situation, a few miles down the highway the car wouldnt go over 45mph, had to do that for a couple hours before we could fix it.

__________________
1991 300 D 2.5 Turbo, 220k
also in the family:
1981 240 D 185k
1991 350 SD 185k
2006 S 500
2005 SLK 350

I change when it begins having difficulty starting and/or poor performance when it is cold out.

Like now. It has been 30,000 and I'll be changing the filters.

__________________
80 300D 340K Owned 30 yrs
83 300SD 440K Owned 9 yrs - Daily Driver 150mi/day
02 Z71 Suburban 117,000
15 Toyota Prius 2600 miles
00 Harley Sportster 24k
09 Yamaha R6
03 Ninja 250

If you wait till you have trouble starting, I'd say you waited way too long, big difference between that and waiting till you feel a slight "miss" under load.

__________________


1985 Euro 240D 5 spd 140K
1979 240D 5 spd, 40K on engine rebuild
1994 Dodge/Cummins, 5 spd, 121K
1964 Allice Chalmers D15 tractor
2014 Kubota L3800 tractor
1964 VW bug

"Lifes too short to drive a boring car"

When it's dirty as indicated by engine performance or if I happen to have it off for another reason (primary or secondary if BabyMog is correct), such as running diesel purge.

__________________
1977 300d 70k--sold 08
1985 300TD 185k+
1984 307d 126k--sold 8/03
1985 409d 65k--sold 06
1984 300SD 315k--daughter's car
1979 300SD 122k--sold 2/11
1999 Fuso FG Expedition Camper
1993 GMC Sierra 6.5 TD 4x4
1982 Bluebird Wanderlodge CAT 3208--Sold 2/13

I have seen the failure of two Caterpillar (mechanical) IPs, one of them mine, very expensive failures. Both of the failures were shortly after "algae" problems leading to almost complete fouling of the (2micron) primary filter which didn't allow enough fuel flow for full-power.

My theory on this, admittedly a complete extrapolation, is that they're related. Fuel pump failure on these is rare and both following fuel-filter problems leads me to this theory.

Considering the pump is partially lubricated by diesel fuel, and that it is capable of creating a ~2000psi rise in pressure, it is also likely that a significant blockage / hydrolock of the supply can create significant vacuum (I always run Racor pressure/vacuum gauges on the fuel supply to indicate filter condition). It is possible that this vacuum can cause problems with seals that have aged 20years of different fuel formulations and heat cycling in our cars, and aren't able to cope with this vacuum without damage. It is also possible that this suction can cause breaches in the filter element (again theory), at least enough that significant contamination can be released from the element.

Anyway, my point is that waiting for the filter to create a blockage and suction enough to affect engine performance is not IMO prudent. The system is not designed to run at a vacuum, and having a fuel filter on-hand whenever the oil is changed just seems like good timing and good prevention.

I might be wrong, after all I am married.

__________________

Gone to the dark side

- Jeff

I do mine with every other oil change. I also do a diesel purge at that time. seemed like cheap insurance...

I also carried a couple spares and always have my tools in the trunk. That's what trunk is for, right?

__________________
"I have no convictions ... I blow with the wind, and the prevailing wind happens to be from Vichy"

Current
Monika '74 450 SL
BrownHilda '79 280SL
FoxyCleopatra '99 Chevy Suburban
Scarlett 2014 Jeep Cherokee
Krystal 2004 Volvo S60
Gone
'74 Jeep CJ5
'97 Jeep ZJ Laredo
Rudolf ‘86 300SDL
Bruno '81 300SD
Fritzi '84 BMW
'92 Subaru
'96 Impala SS
'71 Buick GS conv
'67 GTO conv
'63 Corvair conv
'57 Nomad

That's an interesting hypothesis. Doesn't the fuel shut off solenoid on the Cat do the same thing by cutting off the fuel? Or, is it only the partial shutting off of fuel that causes the problem?
The fuel vacuum gauge is a good means of determining filter replacement.
Another married guy.

__________________
1977 300d 70k--sold 08
1985 300TD 185k+
1984 307d 126k--sold 8/03
1985 409d 65k--sold 06
1984 300SD 315k--daughter's car
1979 300SD 122k--sold 2/11
1999 Fuso FG Expedition Camper
1993 GMC Sierra 6.5 TD 4x4
1982 Bluebird Wanderlodge CAT 3208--Sold 2/13

I'd have to look in the book and refresh my memory, but I believe that the shut-off solenoid in the 3208 modifies rack position to the point where the lifters don't pump fuel. The shutters are rotated to where the fuel spills back out as they are compressed. Since the lifters in the 3208 are immersed in fuel, shutting fuel flow off to the pump would not shut down the engine immediately.

Again, only theory on the suction = damage thing. My pump ate the camshaft, a lifter tore the lobe right off. Ugly. I suppose that a partial vacuum would overcome the spring in the lifter and it might not follow the lobe down, possibly impacting the lobe on the way up and damaging the roller. Once the roller is damaged, life is soon over.

__________________

Gone to the dark side

- Jeff

Are there any hints on replacing the primary and secondary filters on a 616 engine? I've heard things from making sure there is no air bubble in the primary to filling up the secondary with half transmission fluid?? Can someone please shed some light on thie topic??

Thanks!!

An air bubble is a normal part of the filter and nearly impossible to get rid of. It won't harm anything.

ATF should be used in the transmission, not the engine.

I'm not telling.

Tom W

__________________
[SIGPIC] Diesel loving autocrossing grandpa Architect. 08 Dodge 3/4 ton with Cummins & six speed; I have had about 35 benzes. I have a 39 Studebaker Coupe Express pickup in which I have had installed a 617 turbo and a five speed manual.[SIGPIC]

..I also have a 427 Cobra replica with an aluminum chassis.