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        General >> Give/Need advice to/from others >> Diesel coolant system expansion tank mod
        
(Message started by: a-way on Dec 3^rd, 2011, 8:31am)

Title: Diesel coolant system expansion tank mod
Post by a-way on Dec 3^rd, 2011, 8:31am

Hello y'all diesel experts.

As another coolant tank on my diesel scorp has developed a leak from the bolt hole area I was wondering if I could use another coolant tank (new from local dealer was 150eur whan i last asked for the price and i have bought 3 used ones durin 5 years period). How does the coolant move in the hoses? Is it necessary for the tank to be on top of the engine and how exactly the coolant moves in the hoses. I have an understanding that the two bigger hoses that are connected to the bottom of the tank come from so low that i could move the tank lower but i have reservations about the little hose that comes from top of the engine. Will it cause problems if is connected to lower level than it is originally. ???

Title: Re: Diesel coolant system question
Post by gozz on Dec 3^rd, 2011, 9:55am

A header tank must be at the highest point of the cooling system since it is a reservoir and expansion vessel,if it were below the upper level it would be permanently full and lose coolant.
Some older vehicles had a little tank lower down but connected to the top of the radiator by a tube,the idea was that as expanding coolant left the rad it was retained and drawn back as the engine cooled and the liquid contracted,our cars are not in that category.
GOZZ.

Title: Re: Diesel coolant system question
Post by a-way on Dec 30^th, 2011, 9:54am

Naah. I ment if it could be a little lower. Not so much as to develop a leak from the top. 8)

Made the switch during holidays.

Installed a 2.0 expansion tank.

Had to move vacuum valves to different place and custom made the biggest hose which connects to the bottom of the tank.

Also had to modify the cap of the header tank cause it seems that the petrol models have th tiniest hose solely for air as diesel has healthy backflow of coolant from there. ::)

Hope to take some pictures aswell and post them here how the mod came out.

A real moneysaver as the header tank with cap was 5eur and hoses were 6 eur. :D
A "new" used diesel header tank was 32eur as i last enquired.
Already drove ~400km and no problems at all. No leaks etc. Eng temp stay's where it is supposed to be. It plays a little but it did it before aswell. Time to change the thermostat as it appears. 2 years since the last replace.

Title: Re: Diesel coolant system expansion tank mod
Post by a-way on Jan 1^st, 2012, 5:51pm

Pictures at last:

Overall result:

http://i1121.photobucket.com/albums/l510/Kaarel_Heinlaid/Pilt385_v.jpg

Had to move vacuum valves:

http://i1121.photobucket.com/albums/l510/Kaarel_Heinlaid/Pilt389_v.jpg

http://i1121.photobucket.com/albums/l510/Kaarel_Heinlaid/Pilt390_v.jpg

http://i1121.photobucket.com/albums/l510/Kaarel_Heinlaid/Pilt391_v.jpg

Also had to mod the expansion tank cap: had to cut off bottom part where the original seal is, installed seal from the diesel expansion cap, closed 2 holes where air separated previously and made a new one to the top.

http://i1121.photobucket.com/albums/l510/Kaarel_Heinlaid/Pilt005_vaike.jpg

Title: Re: Diesel coolant system expansion tank mod
Post by Tompion on Jan 1^st, 2012, 7:51pm

How have you arranged the overflow/pressure release?

Title: Re: Diesel coolant system expansion tank mod
Post by a-way on Jan 1^st, 2012, 10:19pm

on 01/01/12 at 19:51:16, Tompion wrote:

How have you arranged the overflow/pressure release?

I presume u mean of how the excess pressure leaves the system??? i took the inner part of the cap out and made a hole to the top of it so it works excactly like a cap from the diesel expansion tank... I could take a picture with the cap taken apart again. I wanted to use my original diesel cap but the thread was wrong

I also had a problem with backflow connection because when i started the engine with cap off, coolant bursted right out... so i drilled the hole a little bigger and rounder and installed a little bent copper pipe (with threaded end to screw it in place) so the coolant is directed downward to the tank. I could take a picture of that aswell
Hope i got the question right. English is not my native language. If i didn't u could specify what u ment.

Title: Re: Diesel coolant system expansion tank mod
Post by Tompion on Jan 1^st, 2012, 10:41pm

No picture needed, I just wondered as you were no longer using the 2.3 vent connection as a vent.

Someone on the mailing list who had cooling problems with a diesel found after he flushed the radiator it no longer pumped over into the header tank.

It seems wrong to me that yours pumps into the tank.

Title: Re: Diesel coolant system expansion tank mod
Post by adam on Jan 1^st, 2012, 10:55pm

AFAIK, coolant returning into header tank is correct. I know mine does and two others i have seen also do. The beauty of a clear original td header tank is to see this occur.

Title: Re: Diesel coolant system expansion tank mod
Post by Tompion on Jan 1^st, 2012, 11:32pm

Thanks Adam.

Title: Re: Diesel coolant system expansion tank mod
Post by adam on Jan 2^nd, 2012, 4:18am

Your welcome Dave.

a-way, i believe the original header height design was to prevent air locks and over heating problems. I know some VM derivatives, i.e Jeep can suffer with these issues. Ford probably carried out some research and development and concluded that the extra height would be necessary.
The blocks are strong on the VM but the heads could be better. I would change back to the original height to prevent problems with head failure. This would prevent the risk of air pockets, causing the head to run locally hot.

Adam

Title: Re: Diesel coolant system expansion tank mod
Post by a-way on Jan 2^nd, 2012, 1:49pm

on 01/02/12 at 04:18:52, adam wrote:

...and concluded that the extra height would be necessary...
Adam

Thanks, will consider the advice and look for a better location that would be higher up... might be just enough room over the turbo if i change the location on power steering oil reservoir... then the lowest hose connection could be connected without the S-shape (probable location for airlocks to develop) as it is at the moment and top of the tank would be even higher than the original header tank...

And also i will try to plastic-weld the original tank where it is leaking 8)