First-time diesel owner, I've recently purchased an '84 300D to lovingly restore and have been searching the threads for info on diesel additives. Power Service, Redline, and Lubro Moly seem to be popular. While I have been trying Power Service Diesel Fuel Supplement, and have just ordered some Lubro Moly Hi Test to sample, the previous owner mentioned he added some ATF now and then, which sounded very suspect to me???? Any downside to his practice which I will get to pay my mechanic for later on???

Also, this is the first turbo I've owned without a boost gauge and no appreciable "rush" as the turbo comes to life. How do I know the thing is working?

Thanx as always for the excellent discussions here!

Jeff
'84 300D
'00 ML430

Jeff,
Welcome, and prepare yourself for all sorts of addictive behaviors to be manifesting right in your own driveway.
I drove Saab Turbos (900 & 9000) and was used to the snap of acceleration when the thing would spool up just above 2k rpm. The equivalent of that in these diesels is much more subtle. The best way to familiarize yourself with the feel of the turbo moving your barge is to drive a non-turbo model.
The difference is very noticeable. Also, as you get the motor dialed in, you may discover a great deal of hidden power. That happened for me.
Most of all, this is one of the strongest and friendliest machines I have ever seen. (I drove a Saab 93 Viggen last week; that is a bit of very serious turbo snap).
FYI, ATF has some good detergents in it, but is not formulated for the heat that fuel encounters in the cylinders. I prefer Stanadyne additive. The stuff has almost totally eliminated the nailing I had going on in the #1 cylinder. I ran high doses through with the tank close to empty. Great stuff.

mccan

I've used redline 85+ with good success and recently ran some Lubro Moly diesel purge through as a onetime cleaning exercise. The redline had kept things clean enough that I didn't notice any difference after doing the purge. Be somewhat careful, if on the outside chance you have a California car that has NOT had the trap oxydizer retrofitted with a catalyst you want to be careful about adding any additives. You should be OK with an '84 but just in case spotting a Calif. car is easy. On the Calif. cars the air cleaner is in the way front passenger side corner of the engine compartment while on the 49 state version it's in the center right side over the turbo.

__________________
LRG
1987 300D Turbo 175K
2006 Toyota Prius, efficent but no soul
1985 300 TDT(130K miles of trouble free motoring)now sold

Thanx for the help. Rechecked, and it is a 49-state car in the driveway. I just found an old thread on using Diesel Purge and will try that as well.
Jeff

Jeff,

The easy way to test the turbo operation is with a stopwatch. Clock the car 0-60 on level road. It should be 13-15 seconds. If much slower, say 17-20+, something is wrong - but not necessarily the turbo. If it is slow then you need to connect a pressure gauge with a "T" into the boost line to the ALDA and go for a drive, to check the turbo output.

FYI, I bought my 1984 and after I got it home I discovered the turbo was bad. Actually I think the wastegate was damaged or stuck open. 0-60 time was something like 25 seconds. I replaced the turbo with a used one, which has low boost at 10psi, and that dropped the time to ~18 seconds. That's still not good but it's better than it was. I haven't had time to diagnose further, either fuel tank screen or injection pump are my first guesses...

BTW - Don't use ATF in the fuel. It can leave deposits that aren't good for your engine. Use diesel additive in the tank like Stanadyne or Red Line 85+, or use Diesel Purge as directed. Dr. Booth claims that a quart of dino 10W-30 in the tank can help burn out carbon deposits, but the power will be lower until the oil is gone from that tank.


Regards,

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Dave
Boise, ID
Check out my website photos, documents, and movies!

Honestly, I have used every major brand of additive in my car at one tankful or another and I really can't tell the difference between them. I still get 25 to 26 mpg and it still runs fine whatever I use. There is an old German mechanic near here named Bruno who also suggests a quart of oil in the tank from time to time but I've yet to try it. I think the steady dose of "Italian tune up" I give the car is what helps the most.

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Orland Park, IL
1985 300SD 215,000 miles

Check the white plastic line from the banjo bolt on the rear of the intake to the ALDA (the sort of square "can" on top of the injection pump) for blockage. Check the banjo bolt, too -- they can be plugged from crud from the EGR and blow-by oil.

Ditto for the switchover valve between the intake and ALDA -- you should be able to blow through it with both ends free, and with one end plugged it must not blow out the vent on top. This valve opens if the boost goes too high to prevent the engine from getting damaged. If it is bad, you have no extra fuel and no extra power from the turbo.

The best way to check boost pressure is to find a gauge and "t" it into the boost line.

You may also need to adjust the ALDA for more fuel -- they tend to reduce the extra fuel added as they wear. The quick and dirty check is to look for smoke -- you should be seeing definite black smoke just fluttering over the trunk at full throttle, third gear, 50-55 mph. A lot means other problems, but none at all means lack of fuel.

This can also be caused by plugged fuel filters, but I suspect this is not the case if the car was well maintained.

And, a good hard trip will do wonders for the condition of the engine -- diesels thrive on high load, high speed conditions -- burns all the accumulated crud out.

I would first check for boost, then fuel delivery -- if you have boost problems, adding fuel won't help.

Peter

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1972 220D ?? miles
1988 300E 200,012
1987 300D Turbo killed 9/25/07, 275,000 miles
1985 Volvo 740 GLE Turobodiesel 218,000
1972 280 SE 4.5 165, 000 - It runs!

Don't use ATF!
I have never used it, and never will, as I have heard that it turns into ash and beats the hell out of your valves.
We have different additives up here in BC Canada, and I use them primarily in the winter, when the fuel changes (less lubricant in Winter Diesel, so you need to be kind to your IP) I use a cleaner type of additive frequently, but not with every fill up, and my car does not smoke more than a little bit when cold. In winter I use Hawes and Kleen-Flo diesel additives, however if Red Line is easily available then use it as it is excellent stuff (pricey, though!)

The reasons to use additives are to keep things clean and minimize smoke, and as an enhancement to lubricate your injector pump,(especially important in winter). Additives will give your fuel delivery parts greater longevity. It is worth the expense. You don't need to exceed the recommended mixtures on the can, either, unless your car is smoking a lot. I carry a plastic measuring cup & little funnel in my trunk.

As an addendum to the post I just made...I agree with Billrok about "Italian Tune ups". I attribute the clean strong running of my 250000 mile 617 to accelerating up mountains frequently, (with a properly warmed engine, of course, and then letting it "idle down" for 30 or so seconds after a good hard run). I think this treatment helps keep my old 300D running well, in addition to the use of additives.

I always wondered what was meant by "Italian Tuneup". I was picturing something with pepparoni.
I use Stanadyne myself. I have noticed that my two diesels will always start on the first turn when used. Can be a difficult start with the older MB without.