1.8 Thermostat housing leak

rrr · 26th May 2015, 14:51

About 2000 km after I fitted a rebuilt engine into my 1.8 I noticed some amount of coolant loss under the thermostat housing. Although I used two new genuine Land Rover seals (CDU3858L) on the housing when putting the engine together, I expected one of them could maybe break. However, after the dismantle I discovered no obvious reason for the leak. So, just as a preventive step I purchased two sealing rings of slightly bigger diameter and used these. But alas! After a test drive when the engine got hot the coolant first leaked in drops then sprinkled from the thermostat housing/pipe assembly joint.
I am ready to dismantle the whole thing again, however I am not sure what should be the next reasonable step. When solving the leak for the first time I replaced the seals and used another pipe assembly (very good used one, powder coated). But the old pipe assembly was ok so I did this just for cosmetic reasons... Even the thermostat housing showed no damage or crack.
Would be thankful for any hint from people who have experience with this problem.

Saga Lout · 26th May 2015, 19:03

Quote:

Originally Posted by rrr

About 2000 km after I fitted a rebuilt engine into my 1.8 I noticed some amount of coolant loss under the thermostat housing. Although I used two new genuine Land Rover seals (CDU3858L) on the housing when putting the engine together, I expected one of them could maybe break. However, after the dismantle I discovered no obvious reason for the leak. So, just as a preventive step I purchased two sealing rings of slightly bigger diameter and used these. But alas! After a test drive when the engine got hot the coolant first leaked in drops then sprinkled from the thermostat housing/pipe assembly joint.
I am ready to dismantle the whole thing again, however I am not sure what should be the next reasonable step. When solving the leak for the first time I replaced the seals and used another pipe assembly (very good used one, powder coated). But the old pipe assembly was ok so I did this just for cosmetic reasons... Even the thermostat housing showed no damage or crack.
Would be thankful for any hint from people who have experience with this problem.

I found my thermostat housing leaking last week also, I was doing the head gasket and noticed it. I found that the brass inserts were pulling through the housing when tightening up the bolts. I put longer bolts in and put nuts on the rear to pull it together. It might be the same problem, have a look.
Regards.

DMGRS · 26th May 2015, 21:53

It could be the seal around the thermostat itself - PEF10010. This also seals the two halves of the thermostat together.

Alternatively, new housings are quite cost-effective:
K Series Thermostat Housing - Complete Assy

SD1too · 28th May 2015, 08:08

Quote:

Originally Posted by rrr

When solving the leak for the first time I replaced the seals and used another pipe assembly (very good used one, powder coated).

Hello Robert,

Did you remember to refit both the inaccessible screws which secure the pipe to the side of the engine block? They're essential.

Simon

rrr · 29th May 2015, 06:20

At the moment the problem seems to be solved by a new thermostat housing (Bearmach) which my local LR parts supplier had in stock. Car still waiting for a long test drive during the weekend.
Still, I found no clear reason for the original leak - the pipe shows no damage (and was tightened properly using 2 bolts to the block), old thermostat housing shows no cracks or distortions. Strange. However, I hope I will not go through another antifreeze-mess martyrdom in my garage...
Thanks for advice to all

26th May 2015, 14:51	#1
rrr Regular poster 2001 75 1.8 LHD, 2000 75 1.8 LHD Join Date: Oct 2009 Location: Prague 6 Posts: 68 Thanks: 5 Thanked 1 Time in 1 Post	1.8 Thermostat housing leak About 2000 km after I fitted a rebuilt engine into my 1.8 I noticed some amount of coolant loss under the thermostat housing. Although I used two new genuine Land Rover seals (CDU3858L) on the housing when putting the engine together, I expected one of them could maybe break. However, after the dismantle I discovered no obvious reason for the leak. So, just as a preventive step I purchased two sealing rings of slightly bigger diameter and used these. But alas! After a test drive when the engine got hot the coolant first leaked in drops then sprinkled from the thermostat housing/pipe assembly joint. I am ready to dismantle the whole thing again, however I am not sure what should be the next reasonable step. When solving the leak for the first time I replaced the seals and used another pipe assembly (very good used one, powder coated). But the old pipe assembly was ok so I did this just for cosmetic reasons... Even the thermostat housing showed no damage or crack. Would be thankful for any hint from people who have experience with this problem.

26th May 2015, 21:53	#3
DMGRS Discount MG Rover Spares Rover 75 CDTi, 2x MG ZS180 Join Date: Jun 2011 Location: Hythe, Southampton Posts: 11,354 Thanks: 456 Thanked 3,377 Times in 2,027 Posts	It could be the seal around the thermostat itself - PEF10010. This also seals the two halves of the thermostat together. Alternatively, new housings are quite cost-effective: K Series Thermostat Housing - Complete Assy __________________ Your trusted MG Rover specialist! Tel: 02380 001133 / Email: [email protected] We now have a 'chat' function on our site for even quicker replies. Give it a try! Remember - discount code FORUM5 for 5% off

29th May 2015, 06:20	#5
rrr Regular poster 2001 75 1.8 LHD, 2000 75 1.8 LHD Join Date: Oct 2009 Location: Prague 6 Posts: 68 Thanks: 5 Thanked 1 Time in 1 Post	At the moment the problem seems to be solved by a new thermostat housing (Bearmach) which my local LR parts supplier had in stock. Car still waiting for a long test drive during the weekend. Still, I found no clear reason for the original leak - the pipe shows no damage (and was tightened properly using 2 bolts to the block), old thermostat housing shows no cracks or distortions. Strange. However, I hope I will not go through another antifreeze-mess martyrdom in my garage... Thanks for advice to all