Date:         Mon, 25 Feb 2008 06:30:26 EST
Reply-To:     FrankGRUN@AOL.COM
Sender:       Vanagon Mailing List <vanagon@gerry.vanagon.com>
From:         Frank Grunthaner <FrankGRUN@AOL.COM>
Subject:      Re:      Oil Temps and TDi rp
              m
Comments: To: sfcompost@YAHOO.COM
Content-Type: text/plain; charset="ISO-8859-1"

In a message dated 2/25/08 12:34:05 AM, sfcompost@YAHOO.COM writes:


> Frank, thanks for the treatise on engine longevity and such.  Certainly not 
> what most of us feel or assume is the reality when it comes to taking care 
> of an engine. My question though, is about oil temps. I realize that you have 
> make serious upgrades to the oil cooling system on your van. From what I read 
> and hear from others is that the tdi oil temps climb rapidly over 3200 rpm.  
> Is this your experience as well, and if so, running the tdi at those high 
> revs sounds a bit dicey. Oil coolers and DK trans here I come.
> Sam M.
> 
> 
Sam,

Heat is definitely the enemy of diesel engine longevity. I have emphasized in 
the past that engine oil temperatures are a critical issue and to that end, I 
only use a top quality diesel grade synthetic (Mobil 1Turbo Diesel Truck 
5W-40). I use dual Passat water/oil heat exchangers (often called coolers) and an 
external Audi 5000T oil cooler fan driven. I also use the auxiliary water pump 
as per the JX plumbing diagram. I also use a one quart Accusump oil reservoir 
to buffer possible dry starts and low oil pressure points. Finally, I use the 
VW ABA windage tray along with a baffle plate to minimize sloshing. In the 
current design, this baffle plate is made of 0.080 inch Aluminum riveted to the 
existing vertical baffle cast into the vanagon diesel pan. This is a large 
immersed thermal surface and probably contributes to oil cooling.

Gauges are an important part of my approach. I monitor the oil temperature 
exiting the pump and entering the dual oil filter system. For diagnostics, I 
often monitor the oil leaving the external cooler. Finally, I monitor the EGT 
with a probe placed in the former EGR port of the ALH VNT Turbo manifold. This 
gives me the exhaust gas temperature immediately before the entrance to the 
turbo and at a common flow point from each cylinder. I also use a boost pressure 
gauge and an oil pressure gauge.

For oil temperatures, I quickly warm up to 190 to 195 F. My typical freeway 
oil temperatures are between 210 and 220 F. On a hard run, I will see a maximum 
of 225 F. Running at 4000 rpm on a level road, I initially see (in the 
acceleration to 4000 rpm, temps quickly go from 190 to 210, then drop back to 
200-205. Steady runs at 4500 rpm in the summer with A/C on can bring temperatures up 
to a max of 230 F. On my Speedhut oil temp gauge, I have the emergency 
checkpoint trigger at 235 F. These synthetics are rated for full film strength at 
temperatures above 250 F for extended multihour operation. No particular temp 
surge is seen going above 3200 rpm. In fact the oil temperature and EGT track 
each other very well. Oil temperature and EGT are maximized with full load. Low 
load, low baseline T.

Of course, I have no idea about what are the most critical or necessary parts 
of my system to give these results. Your results will surely vary.

Frank Grunthaner



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