P38A One for you coolant experts...

This site contains affiliate links for which LandyZone may be compensated if you make a purchase.
J

josh00mac

Active Member
Posts
105
Location
London
Dear all - happy new year!

Haven't been on the forum much apart from scouring for a 109 series due to a totally reliable P38! That never lasts does it....

Last year I changed the O rings just above the transmission tunnel and have enjoyed no coolant loss and dry carpets. Recently I have been losing coolant again and have had the following symptoms this week leading to wet carpets again...

1. a trickling sound coming from behind the dash clocks (not loud, sounds like fluid trickling through a system)
2. This week, what I would describe as a puff/hiss on 2 occasions sounding like it is coming from behind the clocks.

I would be very surprised if the lower O rings have gone already as I did the job last year and with my dash now having sound effects I am led to ask you all... Is there a known connection weakness/rubber piping/joints that may have perished in the upper bulkhead near the matrix (if this is there?)

In respect for people's time I have looked through various forums but haven't found anything other than the standard O ring chat.

What do people think? Absolutely love the P38 and would like to get all of the cooling/HEVAC sorted properly so that I don't have to worry about the damage any coolant is doing in my floorpan!

Look forward to advice!

Josh
 
Have you checked your pollen filters ?? If there wet then the seals have gone on the pollen filter covers also the pollen filter drains could be blocked mite be the source of water ingress as for the coolant loss get some UV dye in there band have a good look around with the black light that come with the dye.

Report back
 
Hi all

I have got back underneath the dash to have a look at the O rings - thankfully it is nothing more serious than a leak at the joint BUT it is not due to perished O rings - as per the image below, the coolant is streaming out from where the screw holds the connection together. Whilst running the engine, coolant is coming out at quite a rate which is leading to my loss.

I have tried to tighten the screw but to no avail so my next question is, is there a synthetic washer that I have failed to replace that sits onto the screw? or is it a case of loading it with Loctite when I take it out and replace it? I am also keen to replace the screw with a hex bolt for obvious reasons - does anyone know the correct size thread?
 
Hi all

Have located the leak to the O ring joint BUT it is not due to perished O rings - coolant is leaking from the screw which joins the connection together. Is there a synthetic/rubber washer that I should have replaced when I did the original O ring job? Seems strange but it is coming out from the screw at quite a rate. I have tried to tighten but it is as tight as it will go. Could it be a case or removing, loading with something like Loctite and replacing?

I would also like to replace the screw for something with a hex bolt head - anyone know the exact correct size?

cheers

Josh
 

Attachments

  • screw leak.jpg
    screw leak.jpg
    238.2 KB · Views: 352
  • screw leak.jpg
    screw leak.jpg
    238.2 KB · Views: 184
josh00mac said:
Hi all

I have got back underneath the dash to have a look at the O rings - thankfully it is nothing more serious than a leak at the joint BUT it is not due to perished O rings - as per the image below, the coolant is streaming out from where the screw holds the connection together. Whilst running the engine, coolant is coming out at quite a rate which is leading to my loss.

I have tried to tighten the screw but to no avail so my next question is, is there a synthetic washer that I have failed to replace that sits onto the screw? or is it a case of loading it with Loctite when I take it out and replace it? I am also keen to replace the screw with a hex bolt for obvious reasons - does anyone know the correct size thread?
Click to expand...

Retaining screw should not come into contact with coolant. I would suggest the fitting the screw goes through and flow and return pipes go into is cracked. New matrix needed.
 
I did mine at the weekend. I've replaced mine with a socket head screw. It takes a 4mm Allen key, and is (I think) an M5 thread size.
Wammers will know that bit.

If you do need a new matrix, Google the "P38 Audi heater matrix replacement hack". You could forget about heater O rings forever...
 
Which part of London are you josh ?? Iv just redone my O rings and if not seated properly and if the screw isn't tightened snuff it will continue to leak I removed the large air duck to gain good access as mine didn't seal properly 1st time round am happy to help if needed
 
biketeacherdave said:
Which part of London are you josh ?? Iv just redone my O rings and if not seated properly and if the screw isn't tightened snuff it will continue to leak I removed the large air duck to gain good access as mine didn't seal properly 1st time round am happy to help if needed
Click to expand...
Hi Dave I am in Surbiton. I have no fluid leaking from the bottom of the join in the O rings... It is just coming from the screw. Haven't read about that problem before. Wammers diagnosis spells another job on the cards.
 
Yeah if you have got a crack in the plastic but are you completely sure ??? The O rings are sealed properly ?? The only way to be sure would be to remove that big air vent, simple snuff then you can get a proper look see
 
biketeacherdave said:
Yeah if you have got a crack in the plastic but are you completely sure ??? The O rings are sealed properly ?? The only way to be sure would be to remove that big air vent, simple snuff then you can get a proper look see
Click to expand...
I think I'm sure - as per my photo it's bone dry but coolant dribbling from the screw. Have looked at the job - bit if dash frame cutting coming up. Tempted to get someone to take the dash out and sort everything - blend motors for peace of mind etc. Where do you take it or do you fix everything yourself? When I take it to Sayers MR they are honest about not wanting that sort of job! Don't blame them.
 
There is not need to remove the dash just the speedo binical and the left bracket then cut threw the vent tube near the top and remove, hey presto loads of room to access the O rings and screw/fixing plate.

I'll look up serbiton if its not a mission I'm happy to swing by and help and yes I do all my own work or it would break the bank
 
biketeacherdave said:
There is not need to remove the dash just the speedo binical and the left bracket then cut threw the vent tube near the top and remove, hey presto loads of room to access the O rings and screw/fixing plate.

I'll look up serbiton if its not a mission I'm happy to swing by and help and yes I do all my own work or it would break the bank
Click to expand...
Surbiton is by Kingston and Esher....Thames Ditton, Teddington neck of the woods.
 
Your only 20 miles away if you can hang on until next weekend I can pop over and give you a hand with stripping it down in the mean time you can simple bypass the heater matrix in the engine bay
 
I it is the matrix I tried to do mine in situ which is a no no the starring column is in the way so dash out best option.
 
brianp38dse said:
I it is the matrix I tried to do mine in situ which is a no no the starring column is in the way so dash out best option.
Click to expand...
When you tried to do it Brian did you cut the dash frame? I have tried to read as much I can on the various forums and there is a bit of chat regarding cutting the dash frame but I can't find much about it. I will have another look next weekend.
 
You must log in or register to reply here.

Similar threads

P
Sport Coolant not circulating
Replies
11
Views
715
pllaw
P
B
Mistake with coolant flush?
Replies
11
Views
725
Bellhouse
B
I
Coolant consumption - Discovery 5 (2021) P360
Replies
2
Views
112
IcemintB
I
J
P38 DSE Auto intermittent lack of power after vehicle has been hot
Replies
8
Views
408
brianp38dse
brianp38dse
P
Loss of coolant - 2008 Range Rover
2
Replies
28
Views
2K
lightning
lightning
Back
Top