300d wvo plumbing - PeachParts Mercedes-Benz Forum

dakota3c06 · #1 04-28-2008, 06:15 PM

I know this has been asked in the past but I see a couple of conflicting answers. I installed a two tank system, heat exchanger in the wvo tank. I put a tee on the heater hose and ran a return line to the hose with the aux pump. Do I tee into the hose between the aux pump and the water pump or after the aux pump. I ran it between the aux pump and water pump and I ran it for about 30 minutes. No heat between the engine and wvo tank but engine was at over 100 degree C. Any suggestions?
85 300d 183k

jaoneill · #2 04-28-2008, 06:28 PM

Quote:

Originally Posted by dakota3c06

I know this has been asked in the past but I see a couple of conflicting answers. I installed a two tank system, heat exchanger in the wvo tank. I put a tee on the heater hose and ran a return line to the hose with the aux pump. Do I tee into the hose between the aux pump and the water pump or after the aux pump. I ran it between the aux pump and water pump and I ran it for about 30 minutes. No heat between the engine and wvo tank but engine was at over 100 degree C. Any suggestions?

I would hope that you have another HE in line somewhere prior to the IP, the in-tank is just the beginning.

To answer your question: Assuming that when you refer to "heater hose" you are speaking of the supply side (in the vicinity of the oil filter). Your problem is most likely an air bubble. It usually takes a 45-60 minute drive (sometimes more) to expel all the air in the line, you can let it sit at idle for a week with no results.

Jim

dakota3c06 · #3 04-28-2008, 06:33 PM

You are correct, I put a tee in the heater supply hose off of the cylinder head by the oil filter. It travels to a plate heat exchanger then back to the tank in the trunk. The return line exits the tank and joins the line between the aux pump and the water pump. My question is whether that is the right location for the return line. I read on another post that it was placed after the aux pump. I will loosen the line and try to remove any air bubbles.

jaoneill · #4 04-28-2008, 09:18 PM

Quote:

Originally Posted by dakota3c06

You are correct, I put a tee in the heater supply hose off of the cylinder head by the oil filter. It travels to a plate heat exchanger then back to the tank in the trunk. The return line exits the tank and joins the line between the aux pump and the water pump. My question is whether that is the right location for the return line. I read on another post that it was placed after the aux pump. I will loosen the line and try to remove any air bubbles.

All you will accomplish with loosening the line is a coolant mess. I would recommend that you simply drive the car for a couple of days and keep an eye on the coolant level. It's the up and down hill, acceleration and deceleration, that will eventually work the air out of the system. When I first did mine I had some flow after a 30 mile run into town. At some point the following day (can't remember exactly when, but on an average day I drive 250-300 miles), the temp gauge on the veg line popped up to 180. Haven't had an issue since and I have around 50K on veg.

Line location is fine, you have it after the pump.

Jim

dakota3c06 · #5 04-29-2008, 07:59 AM

I drove it today and it definately helped. After the mess, you were right, I ended up adding a gallon and it seems to definitely be working now. I noticed that my temp guage started to dip a few times during the drive, I assume do to low fluid level and air. After adding a gallon no problem. Thanks. PS, anyone recommend a good heat exchanger for my rear tank? I saw where someone used a stainless steel flex line for a gas range. I tried it and it seems to work but I worry it may not produce enough heat.

notfarnow · #6 04-29-2008, 08:55 AM

Quote:

Originally Posted by dakota3c06

PS, anyone recommend a good heat exchanger for my rear tank? I saw where someone used a stainless steel flex line for a gas range. I tried it and it seems to work but I worry it may not produce enough heat.

You don't want a lot of heat in the tank, ideally just a heated fuel "pick up". The only heat you want back there is JUST ENOUGH to get the oil liquid and flowing up to the final heat exchanger.

pizzachef · #7 04-29-2008, 03:57 PM

Well, I'm glad you got your air bubble out...for next time, you can use a garden hose to push water in one end of the system and out the other, then quickly connect both ends (usually easier with a helper

) That helps, but driving is definitely easier if its already all hooked up.

As to where your return goes, I have mine upstream of the aux pump (I don't think that is between the aux and main water pumps), and I have the aux pump connected to keyed-on power, so it runs whenever the car is on. It helps get the coolant circulating when you're at idle. If you're not going to re-wire the aux pump, then its probably better to return your coolant to the downstream side of the pump so it doesn't inhibit the flow when its off.

biobenz240d · #8 04-29-2008, 08:53 PM

Quote:

Originally Posted by notfarnow

You don't want a lot of heat in the tank, ideally just a heated fuel "pick up". The only heat you want back there is JUST ENOUGH to get the oil liquid and flowing up to the final heat exchanger.

You've got it right . excess heat will cause polymerization of the oil. You'll know when it's polymerized , it will smell like paint thinner. You'll then need to clean everything out because just a little contaminated oil will start the whole process over again. I only put in enough oil for the trip I'll take. In other words ,I'll only put in oil that I can use up within a week. Just my 2 cents