The Dietzl Mod

Ski in NC said:

Probably not a great mod for driving in very low temps. You are losing the thermo tee which heats fuel going to filter.

The fittings are harware store/hydraulic shop off-the-shelf items. Filter head p/n given a few posts up.

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I live in CT. which isn't as cold as New Hampshire; but I don't think that the thermostatic tee valve on our cars is really necesary. I replaced mine with a "Kerma Widget" which looks like an aluminum tee valve that just takes all of the return oil & sends it back to the tank instead of the filter to recirc back to the tandem pump. There are 3 reasons why I replaced the thermostatic tee with the Kerma widget. 1) The valve construction was rather cheesy & there were a # of posts with people that had fuel supply problems because this valve cracked. 2) I would say that 98% of the time this valve should be in the recirc back to the tank position. Every year when I change my Cat 2 micron fuel filter, I order a can of "Diesel Purge" & when the filter is out I put the Diesel Purge where the filter goes, put a couple of short pieces of plastic tubing into the tandem pump supply & the PD injector return into the can of diesel purge and then run the car for about 30 minutes until it burns up the can. When I have done this, I was surprised to see how fast & how hot the return fuel from the PD injectors gets. I just thought that it was more likely to have problems to have this very hot fuel getting recirculated when it shouldn't be as I have never had any cold start issues with the engine getting cold fuel. 3) Before I replaced my thermostatic valve with the Kerma Widget I would try to verify that the thermostatic valve worked by putting it in hot water & then cold water & then blow air into the return port to see if it actually switched from recircing oil to the filter & then back to the tank once it got hot. I never noticed any difference in the operation of this valve when hot versus cold which is why I thought that this device was a cheaply made that might be prone to causing problems the majority of the time when you don't want the hot recirc fuel going back through the filter to the tandem pump.

Ski in NC said:

Probably not a great mod for driving in very low temps. You are losing the thermo tee which heats fuel going to filter.

The fittings are harware store/hydraulic shop off-the-shelf items. Filter head p/n given a few posts up.

Click to expand...

I switched to the "old style" VW filters without the thermo-t back in 2004 and have been running them ever since (much cheaper to get). No issues, whatsoever, in Canadian winter weather.

Encouraging to see no problems up north with clogging. Maybe an electric fuel heater in filter head with cabin switch, could be energized when you get that dreaded "dead pedal" feeling in bitter cold..

No fan of that thermo tee here, with that constant stream of little bubbles...

cattlerepairman said:

I switched to the "old style" VW filters without the thermo-t back in 2004 and have been running them ever since (much cheaper to get). No issues, whatsoever, in Canadian winter weather.

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Can you still get those? I've found them to be NLA from the places I get parts from.

Lots of engines use the screw on bosch type filter, I'm sure they are somehow still available.

I'm still hesitant to get rid of my thermo tee, as I don't think we reliably get good winterized fuel down here in the south, and we do get cold snaps low enough to gel.

Ski in NC said:

Lots of engines use the screw on bosch type filter, I'm sure they are somehow still available.

I'm still hesitant to get rid of my thermo tee, as I don't think we reliably get good winterized fuel down here in the south, and we do get cold snaps low enough to gel.

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Ski in NC said:

Lots of engines use the screw on bosch type filter, I'm sure they are somehow still available.

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I had assumed, possibly incorrectly, that he was referring to the 98 beetle filter which is just like ours but with no thermo tee hole.

pruzink said:

I live in CT. which isn't as cold as New Hampshire; but I don't think that the thermostatic tee valve on our cars is really necesary. I replaced mine with a "Kerma Widget" which looks like an aluminum tee valve that just takes all of the return oil & sends it back to the tank instead of the filter to recirc back to the tandem pump. There are 3 reasons why I replaced the thermostatic tee with the Kerma widget. 1) The valve construction was rather cheesy & there were a # of posts with people that had fuel supply problems because this valve cracked. 2) I would say that 98% of the time this valve should be in the recirc back to the tank position. Every year when I change my Cat 2 micron fuel filter, I order a can of "Diesel Purge" & when the filter is out I put the Diesel Purge where the filter goes, put a couple of short pieces of plastic tubing into the tandem pump supply & the PD injector return into the can of diesel purge and then run the car for about 30 minutes until it burns up the can. When I have done this, I was surprised to see how fast & how hot the return fuel from the PD injectors gets. I just thought that it was more likely to have problems to have this very hot fuel getting recirculated when it shouldn't be as I have never had any cold start issues with the engine getting cold fuel. 3) Before I replaced my thermostatic valve with the Kerma Widget I would try to verify that the thermostatic valve worked by putting it in hot water & then cold water & then blow air into the return port to see if it actually switched from recircing oil to the filter & then back to the tank once it got hot. I never noticed any difference in the operation of this valve when hot versus cold which is why I thought that this device was a cheaply made that might be prone to causing problems the majority of the time when you don't want the hot recirc fuel going back through the filter to the tandem pump.

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??????
guessing here... but could the thermo tee work based on a spring loaded valve so that when fuel from the tanked got cold, the pressure changed and caused the spring to move... vrs warm fuel flowing easily from the tank and forcing warm fuel return to tank. That would make it cheap and reliable based on fuel PRESSURES, not temperature.

Therefore a warm vrs cold water test would show nothing as it doesnt gell until 32 degrees.. and even then the gell vrs solid/liguid temp is almost non existant in water vrs that of diesel fuel.

the thermo tee could even be a small measured hole size and the gelling or jelling would work as well.. wow who would have thought.

turbocharged798 said:

After jelling up a few times with the 99.5 and being stranded in the cold, there is no way in heck would I want to delete the thermo-t.

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After helping many folks try to un-tooef their cars at GTGs only to have it cause by a hairline crack or pinched o-ring letting air into the filter from the thermostatic tee, I was more than happy to delete it from both of my TDIs.

I have never once had a gelling problem anywhere in the Midwest, Canada or mid-Atlantic. Get fresher fuel and a bit of anti-gel if your local suppliers suck or they don't thoroughly winterize for your local conditions.

At some point fresh fuel from the tank must be used, after the recirculated hot fuel from the filter has been consumed. So the thermostat opens, and if the fuel in the tank and the fuel lines is cold and gelled because it wasn't properly winterized, then this fuel oozes into the filter and the engine dies.

Maybe I'm missing something in this argument, but the thermo-T fails to perform the single reason for its existence. I suppose if you just need the engine to run long enough to drive into a heated garage, then it's okay. But it will not keep you from being stranded if you've got a tank of unwinterized fuel.

Note: in the last four years I've had two instances of gelled fuel. In both cases I was later reimbursed by the stations that sold this fuel. But that didn't help me at the time. My point is, I know from experience what the thermo-T can do and what it can't.

scurvy said:

After helping many folks try to un-tooef their cars at GTGs only to have it cause by a hairline crack or pinched o-ring letting air into the filter from the thermostatic tee, I was more than happy to delete it from both of my TDIs.

I have never once had a gelling problem anywhere in the Midwest, Canada or mid-Atlantic. Get fresher fuel and a bit of anti-gel if your local suppliers suck or they don't thoroughly winterize for your local conditions.

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Which thermo-t-untoof method did you use? Widget, old style filter, or Lowes/Home Depot tube?

Bob_Fout said:

Which thermo-t-untoof method did you use?

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Nicktane filter heads.

I always ran the cat 1r-0751 filter on my duramax with the nicktane adapter and was about to purchase the nicktane for the VW but I like the price of this mod a little better and see no reason why this wouldnt filter or flow enough for these little engines. I just ordered the WIX filter head and I'll be at the local Cat shop and ACE hardware tomorrow and it will be on by Wednesday...

I don't see why you can't simply buy a 1/4" barb adapter, thread it into the other input and attach the thermostatic T input there.

I also found this for people in Canada, I thin it's the same thing, but is has some nice mounting brackets too.

http://www.basspro.com/Bass-Pro-Shops-Fuel-Filter/Water-Separator-Kit/product/45681/49674

I have one of those..on my boat!

The thing to consider is fuel compatibility. It may not flow enough with diesel, particularly cold diesel, for a suction fuel system.

Tony

Ski in NC said:

No fan of that thermo tee here, with that constant stream of little bubbles...

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I call it "oxidizer" . . .

(OP - - that is ONE SHINY, SHINY MOTOR!)

Honeydew said:

I had assumed, possibly incorrectly, that he was referring to the 98 beetle filter which is just like ours but with no thermo tee hole.

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Yes, I do use the 98 Beetle filter and have no issues getting them!

Here is a more complete build which I am working on, this will include a Thermostatic Tee return:

1 - Fuel Filter relocation (42770 Wix, 4770 Napa, or any 1/2 inch fuel/water seperator adapter - usually used on boats!) I got mine for about $22 from a marine store.

2 - 3X 3/8 MIP 5/16 FIP and 3X 3/8 to 1/2 bushing (or 3X 1/2 MIP to 5/16 FIP adapters if you can find them) about $3.00 for each barb and bushing set for a total of $9

3 - 2 inches of J30R9 rated 5/16 Inner Diameter tubing - (Goodyear part numbers 65148 thru 65153 & 65161 thru 65163, Gates part number 4241G and 4241M for marine use, Kuriyama part number A4143, NAPA fuel injection hose part H205, Parker 39708 Super-Flex, McMaster Carr Viton rubber tubing part number 5119K51, or any USCG approved fuel line with SAE J1527 type A-1 approval is compatible) got a long piece for $5 and cut what I needed

4 - 2X crimp style 3/8" hose clamp

5 - Screw on Fuel filter (Wix, Hengst or other brand) $15-$20

6 - Bicycle brakes $2

7 - Can of diesel purge $13

Part 1 - the filter mount assembly
Use one of the plugs on an exit line, only 2 in and 1 out line are required.
Put the assembled barbs/bushings into the two in lines and the remaining out line.
Attach the new 2" line to one of the in barbs, then attach the bottom of the tee (which would usually go into the filter) to the the line and secure both with the crimp clamps.
Attach the in and out to their proper barbs and secure with OE clamps.

2 - making a way to hold the screw on canister
Attach the bicycle brakes to the inside of where the original filter would have gone
Bolt them on securely.

3- putting it together
Prime the new filter with a can of Diesel Purge
Attach the filter to the mount
Tighten the filter holder, don't over tighten it and deform your new filter!

witchcraftz said:

Here is a more complete build which I am working on, this will include a Thermostatic Tee return:

1 - Fuel Filter relocation (42770 Wix, 4770 Napa, or any 1/2 inch fuel/water seperator adapter - usually used on boats!) I got mine for about $22 from a marine store.

2 - 3X 3/8 MIP 5/16 FIP and 3X 3/8 to 1/2 bushing (or 3X 1/2 MIP to 5/16 FIP adapters if you can find them) about $3.00 for each barb and bushing set for a total of $9

3 - 2 inches of J30R9 rated 5/16 Inner Diameter tubing - (Goodyear part numbers 65148 thru 65153 & 65161 thru 65163, Gates part number 4241G and 4241M for marine use, Kuriyama part number A4143, NAPA fuel injection hose part H205, Parker 39708 Super-Flex, McMaster Carr Viton rubber tubing part number 5119K51, or any USCG approved fuel line with SAE J1527 type A-1 approval is compatible) got a long piece for $5 and cut what I needed

4 - 2X crimp style 3/8" hose clamp

5 - Screw on Fuel filter (Wix, Hengst or other brand) $15-$20

6 - Bicycle brakes $2

7 - Can of diesel purge $13

Part 1 - the filter mount assembly
Use one of the plugs on an exit line, only 2 in and 1 out line are required.
Put the assembled barbs/bushings into the two in lines and the remaining out line.
Attach the new 2" line to one of the in barbs, then attach the bottom of the tee (which would usually go into the filter) to the the line and secure both with the crimp clamps.
Attach the in and out to their proper barbs and secure with OE clamps.

2 - making a way to hold the screw on canister
Attach the bicycle brakes to the inside of where the original filter would have gone
Bolt them on securely.

3- putting it together
Prime the new filter with a can of Diesel Purge
Attach the filter to the mount
Tighten the filter holder, don't over tighten it and deform your new filter!

Click to expand...

When you get this done add some pictures with your steps. This will make a GREAT addition to some of the How-To's on here.

Nice mod, a good way to get rid of the thermo-T if not else.
There's electric filter heaters that wraps around the filter, like a very wide clamp. Really effective, the whole filter felt warm to the touch even on very cold winter days. I had one on a Isuzu pickup and would buy one if I did this mod.
I'm happy with the OEM setup though, I haven't heard that it doesn't filter good enough and so far I have no issues with the thermo tee's or gelling.

Anyone plumb up the thermo tee yet? I would love to see some pics of it to see how it was done.

I'm working on it. Just tested a proof of concept yesterday. I will upload pictures with my DIY posted above once I've done a final test with it running, I'll be driving it 2000 Km from Vancouver, BC to Calgary, AB this weekend.

witchcraftz said:

I'm working on it. Just tested a proof of concept yesterday. I will upload pictures with my DIY posted above once I've done a final test with it running, I'll be driving it 2000 Km from Vancouver, BC to Calgary, AB this weekend.

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Sounds great looking forward to seeing it.

this might be useful, might not:

Cat filter 1R-0749/P551311 uses 1"-14 threads
Also 1R-0755, still 2 micron absolute filter, but 46% larger OD, and 29% taller and has 1⅜"-16 threads.
Volume of 1R-0749 is 100 cubic inches, or 0.43 gallons, 1R-0755 is 273 cubic inches, or 1.18 gallons.

0749 is available and cheap ($9-19) and are in three lengths, also a water-separator(but much less filter efficiency). Base can be cheap($18-$50).
Cat filters rated at 98% 2 micron, Donaldson 99% and are only ones considered absolute.
Fleetguard 94% 2 micron.

BF1212 is best for emulsified water removal 95%.
Below is info compiled from http://beyondbiodiesel.org/forum/index.php?topic=48.0:

FILTER HEADS (1-14" Thread)
Cat -280-2698
Donaldson P174777, Fleetguard 3304173S, fleetguard base 142784S and the Baldwin OB1308.
Perma-Cool 88864 High Flow Filter Head (1/2 NPT Inlet / Outlet)
Perma-Cool 81074 Fuel Filter/Water Separator Kit (1/2 NPT Inlet / Outlet)
Perma-Cool 81794 High Performance Filter Head (3/4" NPT Inlet / Outlet)
Fleetgaurd 142784S (1/2 NPT Inlet / Outlet)
Donaldson P174768 (7/8-14UNF)
Baldwin FB1311 (7/8-14 UNF Inlet / Outlet)
Fleetguard 3930618-S ( 1/2-14 )
Fleetguard 212013S ( 7/8- 14 ) This is the Dual Mount!
NAPA 4770
Wix 24770

FILTER NUMBERS

Cat Primary Filter/Water Separator 175-2949 (threads 1-14 UNS-2B )
Fleetguard FS19683
Donaldson P551743
Baldwin BF1268
Wix 33005
Luber-Finer LFF8030
ACDelco TP1002

Longer 11-12":
Cat Secondary Filter 1R-0749 (2 Micron) (threads 1-14 UNS-2B )
Fleetguard FF5319
Donaldson P551311
Baldwin BF7587 (BF614, Standard Version, BF7633, Short Version)
Wix 33674
Luber-Finer LFF2749 (High efficiency version of LFF5823B)
ACDelco TP1322
Fram P8335
Purolator F75185
Hastings FF1056 (FF1007, Standard Version FF1079, Short Version))

Shorter:
Cat 1R-0750 (2 micron) (threads 1-14 UNS-2B )
Fleetguard FF5320
Donaldson P551313
Baldwin BF7633 (BF7587, Long Version)
Wix 33528
Luber-Finer LFF3347
ACDelco TP1326
Fram P8334
Purolator F65213
Hastings FF1079 (FF1056, Long Version)

witchcraftz said:

I'm working on it. Just tested a proof of concept yesterday. I will upload pictures with my DIY posted above once I've done a final test with it running, I'll be driving it 2000 Km from Vancouver, BC to Calgary, AB this weekend.

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Get'er done yet? Anxiously awaiting to hear and see the outcome.

I have a good qaulity pad heater on a 12v relay and switch attached to my fuel filter canister.I am a retired truckdriver so I know about jelling. I havn't needed to use it yet because last winter here in Ct. was mild but it's there waiting if needed. If anyone is thinking of doing that just don't buy a cheap one and make sure it is fused.The cheap ones can be a fire hazzard.

Sorry, I haven't posted the how to but I can say it worked flawlessly. I just want to make a small change in the setup and then I'll make a full thread on it tomorrow.

I've been delayed due to other problems taking a priority, like the ABS issues I'm having lol.

Just a heads-up, if you get one of these filter bases check the alignment of the nipple in relation to the sealing surface. I just redid the fuel system on my truck and this filter base was part of the new system. The nipple on the base I got was leaning at a slight angle. Installed anyway because I was past the point of no return and had a slow drip for a week until I got a new base from my supplier.

I was going to post the whole updated thread here but the supplier didn't come through today.

So I will simply post a "this is what I'm going to do next" update:

My current setup has a small tube going from the Thermostatic Tee to a 5/16 barb on the "in" side of the base. Each side of the tube is held into place by clamps.

This works well but is not as esthetic as I want, I want to make this Mod good looking as well as functional. So I am sourcing something that looks like this piece:


With this I will thread the back side into my Base (with an adapter) and the inlet side should simply be a matter of pushing the button, inserting the Thermostatic Tee, letting go of the button, and it will lock into place. This piece is made of chemically resistant (including diesel) plastic or metal and can withstand up to 120 PSI without leaking.