Author |
Topic: Diesel coolant system expansion tank mod (Read 2092 times) |
|
a-way
Newbie
Posts: 39
|
 |
Diesel coolant system expansion tank mod
« on: Dec 3rd, 2011, 8:31am » |
 Quote  Modify
|
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. 
|
|
 IP Logged |
F Scorpio GHIA 2,5tdi 125bhp MT
|
|
|
gozz
Senior Member
Been around awhile
Posts: 3475
|
|
Re: Diesel coolant system question
« Reply #1 on: Dec 3rd, 2011, 9:55am » |
Quote Modify
|
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.
|
|
IP Logged |
|
|
|
a-way
Newbie
Posts: 39
|
|
Re: Diesel coolant system question
« Reply #2 on: Dec 30th, 2011, 9:54am » |
Quote Modify
|
Naah. I ment if it could be a little lower. Not so much as to develop a leak from the top. 
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. 
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.
|
|
IP Logged |
F Scorpio GHIA 2,5tdi 125bhp MT
|
|
|
a-way
Newbie
Posts: 39
|
|
Re: Diesel coolant system expansion tank mod
« Reply #3 on: Jan 1st, 2012, 5:51pm » |
Quote Modify
|
Pictures at last:
Overall result:
Had to move vacuum valves:
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.
|
|
IP Logged |
F Scorpio GHIA 2,5tdi 125bhp MT
|
|
|
Tompion
Administrator
1997 2.3 Ultima estate.
Posts: 2918
|
|
Re: Diesel coolant system expansion tank mod
« Reply #4 on: Jan 1st, 2012, 7:51pm » |
Quote Modify
|
How have you arranged the overflow/pressure release?
|
|
IP Logged |
ABS multiplug wheel sensor pins MK IV or MK 20
|
|
|
a-way
Newbie
Posts: 39
|
|
Re: Diesel coolant system expansion tank mod
« Reply #5 on: Jan 1st, 2012, 10:19pm » |
Quote Modify
|
on Jan 1st, 2012, 7:51pm, 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.
|
|
IP Logged |
F Scorpio GHIA 2,5tdi 125bhp MT
|
|
|
Tompion
Administrator
1997 2.3 Ultima estate.
Posts: 2918
|
|
Re: Diesel coolant system expansion tank mod
« Reply #6 on: Jan 1st, 2012, 10:41pm » |
Quote Modify
|
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.
|
|
IP Logged |
ABS multiplug wheel sensor pins MK IV or MK 20
|
|
|
Scorpio
Full Member
Posts: 562
|
|
Re: Diesel coolant system expansion tank mod
« Reply #7 on: Jan 1st, 2012, 10:55pm » |
Quote Modify
|
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.
|
|
IP Logged |
|
|
|
Tompion
Administrator
1997 2.3 Ultima estate.
Posts: 2918
|
|
Re: Diesel coolant system expansion tank mod
« Reply #8 on: Jan 1st, 2012, 11:32pm » |
Quote Modify
|
Thanks Adam.
|
|
IP Logged |
ABS multiplug wheel sensor pins MK IV or MK 20
|
|
|
Scorpio
Full Member
Posts: 562
|
|
Re: Diesel coolant system expansion tank mod
« Reply #9 on: Jan 2nd, 2012, 4:18am » |
Quote Modify
|
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
|
|
IP Logged |
|
|
|
a-way
Newbie
Posts: 39
|
|
Re: Diesel coolant system expansion tank mod
« Reply #10 on: Jan 2nd, 2012, 1:49pm » |
Quote Modify
|
on Jan 2nd, 2012, 4:18am, 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
|
|
IP Logged |
F Scorpio GHIA 2,5tdi 125bhp MT
|
|
|
|
Home
Help
Search
Members
Login
Reply
Send Topic
Print