leaking coolant through radiator cap

BX Tech talk
citronut
Over 2k
Posts: 2781
Joined: Wed Oct 31, 2007 7:55 am
Location: EAST SUSSEX UK

Re: leaking coolant through radiator cap

Post by citronut » Tue May 19, 2015 8:29 am

oladiti wrote:So far I have carried out the 50 seconds test, there was pressure built-up, with a hisss! sound when cap was open, but no eruption.

I then went on to run the engine with cap off, slight bubbles soon clear away and water remain stable for about a minute and then!
the water level slowly rises up to the little safety hole on radiator neck, I mob this off with a rag and pop back the cover and went on to try and run car up to running temperature to encourage the fan to cut-in, but before that temperature could be reached the water/coolant started flowing out of the cap.

Switched ignition off and left car for about 2 hours, Upon my return, I decided to open the cap with a rag, even though the radiator had sufficiently cooled down, turned the cap slowly the water erupted on to my face.

Also one other thing I noticed was that only the top part of the radiator that is getting hot

Tomorrow 19/5/15 I will be conducting a chemical test at my local garage.
run it with the cap off till it erupts as the rise in coolant can just be trapped air in the system,,

once it has chucked up/out what it wants re/top the system and continue running with the cap off till the coolant sinks, then top up as required till it stops sinking,
Tim Leech wrote: I can't see any leaks but the cars running ok and doesn't seem to be smoking and the heaters hot.

I'll keep an eye on it.

sorry if i missed something Tim, but if this is a diesel they usually just pressurise the system and chuck it out through the tank cap if they have H/G failure,

they will also push out coolant if the tank is above the correct level

regards malcolm
curent ride
K reg BX 17TD TZD est
also own
K reg D special

no longer have
H reg CX saffari 2.5 TRI (now gone to Malaysia)
R reg xantia 1.9TD est (gone to meet its maker)

User avatar
Thread Bear
1K Away
1K Away
Posts: 1651
Joined: Sat Jun 08, 2013 9:47 am
Location: Longcot, near Faringdon, Oxfordshire
x 1

Re: leaking coolant through radiator cap

Post by Thread Bear » Tue May 19, 2015 9:03 am

If this is a new radiator then there is/was a blockage elsewhere, if the lower part is not hot. Not enough water going round. Does the heater work and turn off?

Sounds like clag attack to me. Trouble is it might have taken the gasket out already. Playing brinkmanship with cooling on the BX is a losers game as they are known to be poor, exasabated by no temperature guage in many specs. Being the narrowest place any clag will happily pollute a nice new radiator, if the whole system was not cleaned out prior to its fitting. So if this was not done the rad is now suspect.

Of course a dying radiator is often treated with anti leak rad-weld type product. This adds to the clags negative effects making it into semi permanent solids, rather than a drifting sand bank. Heater systems can be greatly affected with the muck, even creating a one way valve, effectively, if the weld was put in when the heater was not fully in use.

If the system is clean, and the thermostat works, or is temporarily removed, than the system should take in water to be bled full - a quoted figure in the book so you can know this is so by prior measurement of your supplies, it should work. The fan should come on at the appropriate time. Champagne activity means a hangover, duff gasket time.

If the heater works then that is sufficient to get most cars home, if the radiator fans fail, or there is a loss of some water or radiator efficiency, for instance. I have done this many times in my years of banger driving. The heater is a most useful device, far more then just keeping you warm. Always have your heater working in your banger, it saves a lot of dosh over time.
Miguel - 16 TRS Auto S, light blue, 43k miles - £450
Pluto - 14 E S, White, 105k Miles - in work
Egbert - 19 16v Gti, White, A/C & Leather, - Keeper
Walt - 17 TZD Turbo S, graphite, 70k miles, good op extras - Keeper
Scraper- 17 TZD Turbo E, blue, 208k miles - parts
Homer - 19 TXD E, Red, 189k miles - £250
Gary - 17 TZD Turbo E, 118k miles - in work

'87 Trooper, Borgwards, Saabs, MG ZB, Bellamy Trials, Fiat Jolly & Bianchina, Goggo Dart, Messerschmitt, Heinkel, Bubblecars

User avatar
Kitch
Over 2k
Posts: 6218
Joined: Sun Jul 03, 2005 9:36 pm
Location: Fareham, Hants
x 54

Re: leaking coolant through radiator cap

Post by Kitch » Tue May 19, 2015 10:08 am

I'm edging more towards HGF now. Sounds like the cap isn't actually leaking to me?

You need a get a leakdown test done. If there's a leak, you'll find it.
The national BX register - click to submit a car!

1983 16TRS (Sunrise red) - 1987 DTR Turbo est (Venetian red) - 1989 16 Valve (Venetian red) - 1990 16 Valve (Venetian red)

User avatar
Tim Leech
Over 2k
Posts: 15222
Joined: Tue Apr 15, 2008 11:12 am
Location: Burton on Trent
My Cars: 1958 ROVER P4 90 UWP 84
1963 VW BEETLE 1200 KGJ413A
1972 Morris Marina 1.8 SDL BFA720L
1979 Rover SD1 3.5 V8-S TSL 982
1980 Morris Marina 1.7HL DBV468W
1985 CITROEN BX 19GT C1TBX
1991 CITROEN BX 19TZI AUTO A/C BXi 19
1994 CITROEN XANTIA 1.8 SXi M908HRY
2003 Rover 25 1.6i XL L33CHT
x 85

Re: leaking coolant through radiator cap

Post by Tim Leech » Tue May 19, 2015 7:02 pm

citronut wrote:
oladiti wrote:So far I have carried out the 50 seconds test, there was pressure built-up, with a hisss! sound when cap was open, but no eruption.

I then went on to run the engine with cap off, slight bubbles soon clear away and water remain stable for about a minute and then!
the water level slowly rises up to the little safety hole on radiator neck, I mob this off with a rag and pop back the cover and went on to try and run car up to running temperature to encourage the fan to cut-in, but before that temperature could be reached the water/coolant started flowing out of the cap.

Switched ignition off and left car for about 2 hours, Upon my return, I decided to open the cap with a rag, even though the radiator had sufficiently cooled down, turned the cap slowly the water erupted on to my face.

Also one other thing I noticed was that only the top part of the radiator that is getting hot

Tomorrow 19/5/15 I will be conducting a chemical test at my local garage.
run it with the cap off till it erupts as the rise in coolant can just be trapped air in the system,,

once it has chucked up/out what it wants re/top the system and continue running with the cap off till the coolant sinks, then top up as required till it stops sinking,
Tim Leech wrote: I can't see any leaks but the cars running ok and doesn't seem to be smoking and the heaters hot.

I'll keep an eye on it.

sorry if i missed something Tim, but if this is a diesel they usually just pressurise the system and chuck it out through the tank cap if they have H/G failure,

they will also push out coolant if the tank is above the correct level

regards malcolm
Hi Malc

It's using/loosing water quite a lot and the low water lamp comes on, I'm topping it up weekly by about a litre or so, which isn't as it should be.
1963 VW BEETLE 1200
1985 BX 19GT Mk1
1985 BX 19 DTR Mk1
1991 BX 19TZI Auto A/C
1994 Xantia 1.8i SX
1972 Morris Marina 1.8 SDL
1979 Rover SD1 V8-S
1980 Morris Marina 1.7 HL
2003 Rover 25 1.6i XL 5 DR

citronut
Over 2k
Posts: 2781
Joined: Wed Oct 31, 2007 7:55 am
Location: EAST SUSSEX UK

Re: leaking coolant through radiator cap

Post by citronut » Wed May 20, 2015 8:46 am

Thread Bear wrote:If this is a new radiator then there is/was a blockage elsewhere, if the lower part is not hot.
the lower part can be cold if there is trapped air in the system,

im not saying the H/G has not failed, or there is no blockage,

but in my experience on bleeding a BX or most PSA c ars, they bleed quite easy if my technique is followed,

after using this technique and it still pressurises on following this method for a second time, it then is almost certainly H/G faliure, or a possible blockage,

regards malcolm
curent ride
K reg BX 17TD TZD est
also own
K reg D special

no longer have
H reg CX saffari 2.5 TRI (now gone to Malaysia)
R reg xantia 1.9TD est (gone to meet its maker)

oladiti
New Member
Posts: 15
Joined: Thu Oct 30, 2014 8:09 pm

Re: leaking coolant through radiator cap

Post by oladiti » Thu May 21, 2015 12:42 am

thanks malc, tim, kitch, thread bear and ALL....

I had the chemical leakdown test done yesterday 19/5/15 and yes the blue liquid turned green. however not conclusively,
because the guy who carried out the test had to do it twice as you couldn't see any difference in the first.

I have spoken to Lawrence who I got the car from and he has kindly accepted he is more than happy to purchase and replace the head gasket, the car is on the Touareg UK thread. Also he supplied the brand new radiator, this was fitted before I collected the car. Lawrence is an amazing guy, I have nothing but admiration for him, he's a gentleman in all sense.

I will keep you all posted
regards Ollie

User avatar
ken newbold
Over 2k
Posts: 4408
Joined: Sun Aug 14, 2005 10:53 pm
x 5

Re: leaking coolant through radiator cap

Post by ken newbold » Thu May 21, 2015 10:16 pm

I think if you'd mentioned that the car had boiled up on the way home from Lawrence's place after having the new rad fitted the conclusion to this thread would have been much quicker.

I'm sure Lawrence is a nice guy but over the years there has been so much talk on here about bleeding these things I can't believe this has happened to what was a perfect engine.

Seriously pissed off for my old car :(
They think it's all over, it is now!

citronut
Over 2k
Posts: 2781
Joined: Wed Oct 31, 2007 7:55 am
Location: EAST SUSSEX UK

Re: leaking coolant through radiator cap

Post by citronut » Fri May 22, 2015 8:42 am

ken newbold wrote:I think if you'd mentioned that the car had boiled up on the way home from Lawrence's place after having the new rad fitted the conclusion to this thread would have been much quicker.

:roll: #-o

i get this quite a lot with some of my customers not telling me the hole story, then they expect you to get your crystal balls
( spheres ) out,

and they wonder why it took so long to get to the bottom of the issue

regards malcolm
curent ride
K reg BX 17TD TZD est
also own
K reg D special

no longer have
H reg CX saffari 2.5 TRI (now gone to Malaysia)
R reg xantia 1.9TD est (gone to meet its maker)