Now this is a curiouis one...Coolant over pressure and overheat....

As ya'll know, I am having a mare with the L322 at the moment...

2 weeks ago it overheated and over pressure due to air lock in the cooling system.

Thought I had traced this to a duff stat....so whipped off the stat and removed the internals and put it back, for the last 2 weeks she has been flawless..................................until today.

Ran fine then I filled up with LPG as it was getting low (Fill light flashing) so filled up and got about a mile up the road....temp in red and COOLANT TEMP warning on dash.

**** bugger fart.....

Hoses solid, coolant ****ing out of the cap and no heat in the heater....air lock - again.

Now here is the curious part, she has been fine for the last two weeks...looking back at the fill ups I have done, she was last filled up when she over heated last time...then fine....and now she has done it again after an LPG fill up.

Wil2813 mentioned in a previous thread that maybe the LPG vap has a leak from the gas side to the coolant side....I am now considering this to be the case (not that I doubted him in the first place) so I will disconnect the vap from the cooling system, unplug the gas solenoids so the can't operate and run her on petrol for a while and see how she fairs!

Thoughts in the mean time??

Just off the top of my head are you sure the water pump is ok, and I'm not sure what vaporiser you have but it might be worth giving the guys at Tinley Tech a ring or email, I've found the very helpful. I can't see the gas / water thing but they'd be able to give you an answer. Lastly, how is it plumbed in, I'm thinking line of least resistance and the water is not flowing around it all?
Hope some of this helps.

Thought you had done this weeks back. Seems a no brainer to me. You could try by passing the water pipes as mentioned and do a forced start on gas to get around the cold vaporiser sensor and see if you get gas from the water side of the vap.

forthbridge said:

Just off the top of my head are you sure the water pump is ok, and I'm not sure what vaporiser you have but it might be worth giving the guys at Tinley Tech a ring or email, I've found the very helpful. I can't see the gas / water thing but they'd be able to give you an answer. Lastly, how is it plumbed in, I'm thinking line of least resistance and the water is not flowing around it all?
Hope some of this helps.

Click to expand...

Will be checking flow, although 2 weeks previous flow was good.

The system is the BRC Sequent. in the vap is a seal that seperates the coolant side from the gas side, as the coolant system keeps the vap warm and prevents freezing. if the seal is leaking, the HP gas could get into the cooling system causing a huge air/gas pocket!

rewmer said:

Thought you had done this weeks back. Seems a no brainer to me. You could try by passing the water pipes as mentioned and do a forced start on gas to get around the cold vaporiser sensor and see if you get gas from the water side of the vap.

Click to expand...

Not sure how to do a forced start on the BRC system! any clues?

Not sure but you could try holding the changeover button as you turn on the ignition, keep it held until the lpg light goes solid.

Sounds like you have some things to try out. If you take the vapouriser out of line maybe it would be worth blanking off the pipes that way you won't get a flow circuit through the free line which would have less resistance than the line through the heater. In effect returning your rangie to pre lpg days. I changed my rad just after you published your how to, so your procedure works. Last thought, how's the belt tension. When I did the rad both were knackered, belt tension after this was much better. Good luck with it.

Saint.V8 said:

...so I will disconnect the vap from the cooling system, unplug the gas solenoids so the can't operate and run her on petrol for a while and see how she fairs!

Click to expand...

What a royal pain!

I guess it can only be a leak or fluid or air getting in. I've got nought to add apart from disconnect the vaporiser as said (I wouldn't have thought of that) .....but instead of disconnecting the gas solenoids could you not just pull the LPG fuse(s). You can on my PRINS system - perhaps that's what you meant anyway.

Charlie

Is the viscous fan okay? Just a thought...

charliedurrant said:

Is the viscous fan okay? Just a thought...

Click to expand...

VC on fan is new, replaced mid September.

OK....

Sunday, undid expansion cap (Rad hoses soft - car has stood for 24 hours) there was a release of pressure from the expansion tank and some gurgling noises from the tank.

Monday, Car hasn't moved since Saturday or been started since Saturday....undid expansion tank cap....again a release of pressure and some gurgling noises....something has introduced pressure into the cooling system since Sunday, engine hasn't run, so can only assume it is the LPG vap leaking.

Will be disconnecting the vap coolant hoses, and if I can find if my tank as a manual isolation valve I will isolate the gas supply there, pull the electrical connections to the solenoid valves and manual switch to petrol to take the LPG system out of the loop and see if there is an increase in pressure tomorrow.

Does seem uncanny that this issue arises when we fill with LPG.

Also will be ordering a reseal kit for the vap and new filters in the meantime!

Saint.V8 said:

OK....

Sunday, undid expansion cap (Rad hoses soft - car has stood for 24 hours) there was a release of pressure from the expansion tank and some gurgling noises from the tank.

Monday, Car hasn't moved since Saturday or been started since Saturday....undid expansion tank cap....again a release of pressure and some gurgling noises....something has introduced pressure into the cooling system since Sunday, engine hasn't run, so can only assume it is the LPG vap leaking.

Will be disconnecting the vap coolant hoses, and if I can find if my tank as a manual isolation valve I will isolate the gas supply there, pull the electrical connections to the solenoid valves and manual switch to petrol to take the LPG system out of the loop and see if there is an increase in pressure tomorrow.

Does seem uncanny that this issue arises when we fill with LPG.

Also will be ordering a reseal kit for the vap and new filters in the meantime!

Click to expand...

Know sod all about LPG other than it burns. But that sounds a reasonable assumption Ant. Can you not stick some Andrews in the header tank, it gets rid of my excess gas no problem.

Would there not be some residual smell coming from the coolant system when you release the cap if there was a leak from the gas side to the coolant side?

wammers said:

Know sod all about LPG other than it burns. But that sounds a reasonable assumption Ant. Can you not stick some Andrews in the header tank, it gets rid of my excess gas no problem.

Click to expand...

Or hold a lighted match next to the tank cap when you unscrew it, get rid of all your problems if it's gas

Further update:

LPG Vap is off and the Coolant pipes looped using stainless steel fittings.

LPG Solenoid blanked with sealing plug and copper washer (helps working in the Aircraft industry...alsorts of fun hydraulic/pneumatic/aircraft parts we can use to fix stuff )

LP|G to Injector Pipe blanked with an M12 Bolt, Manifold Pressure Sensor pipe (?) plugged with an M8 bolt and tied up out of the way.

Cooling system filled and bled, and driven the 26 miles home (remember still not stat fitted).....

No issues, Temp remained in the 75-81degC range, heater is hot again and other than the £105 it cost to fill with petrol (have never put more than £20 in before) all seems well.

Will run this Tank of petrol through and see how she fairs and in the meantime I will reseal the vap and do the LPG filters while it is all disconnected - How To will be written obviously!

Also I will be looking to try and sort the Diagnostic failure issues and she needs a fluid change on GB, Engine, Diffs and TB so I will do them too while we have the Fiat 500 out of retirement so the GF and our Baby Girl can get around (Fiat has the ISOFix mounts otherwise she would be driving the P38)....

Watch this space!

Saint.V8 said:

Further update:

LPG Vap is off and the Coolant pipes looped using stainless steel fittings.

LPG Solenoid blanked with sealing plug and copper washer (helps working in the Aircraft industry...alsorts of fun hydraulic/pneumatic/aircraft parts we can use to fix stuff )

LP|G to Injector Pipe blanked with an M12 Bolt, Manifold Pressure Sensor pipe (?) plugged with an M8 bolt and tied up out of the way.

Cooling system filled and bled, and driven the 26 miles home (remember still not stat fitted).....

No issues, Temp remained in the 75-81degC range, heater is hot again and other than the £105 it cost to fill with petrol (have never put more than £20 in before) all seems well.

Will run this Tank of petrol through and see how she fairs and in the meantime I will reseal the vap and do the LPG filters while it is all disconnected - How To will be written obviously!

Also I will be looking to try and sort the Diagnostic failure issues and she needs a fluid change on GB, Engine, Diffs and TB so I will do them too while we have the Fiat 500 out of retirement so the GF and our Baby Girl can get around (Fiat has the ISOFix mounts otherwise she would be driving the P38)....

Watch this space!

Click to expand...

Well......

Got to the car this morning, decided to check the coolant level....undid the cap and there was a hiss and then about half a litre of coolant bubbled out, this is after standing for over 12 hours overnight!

The tank was full of water, opened the bleed screw and the level dropped right down, so filled up with a litre or so and did my best at 6am in the morning rain and wind to bleed the system.

Last night on the way home, she was 2-3degC warmer than usual (no stat fitted) but nothing untoward, on the way to work this morning with the heater full on, the temp of the airflow varied with engine speed.....

Considering changing the water pump (again - last changed 18 months or so ago) and see if that changes things!

If it isn't that, I will do a CO2/CO test on the expansion tank and see what gives....

Saint.V8 said:

Well......

Got to the car this morning, decided to check the coolant level....undid the cap and there was a hiss and then about half a litre of coolant bubbled out, this is after standing for over 12 hours overnight!

The tank was full of water, opened the bleed screw and the level dropped right down, so filled up with a litre or so and did my best at 6am in the morning rain and wind to bleed the system.

Last night on the way home, she was 2-3degC warmer than usual (no stat fitted) but nothing untoward, on the way to work this morning with the heater full on, the temp of the airflow varied with engine speed.....

Considering changing the water pump (again - last changed 18 months or so ago) and see if that changes things!

If it isn't that, I will do a CO2/CO test on the expansion tank and see what gives....

Click to expand...

Oh dear sounds a little ominous Ant.

wammers said:

Oh dear sounds a little ominous Ant.

Click to expand...

Not sounding great is it Tony!?!

No signs on the oil cap of any moisture getting in, the beast runs smooth and powerful, no stuttering or hesitation, no struggling to start, no smell of exhaust in the coolant (but is a bit musty), no oil in the coolant, no blockages and the water pump will shot water out of the expansion tank weep hole and/or bleed screw so I can only assume water is fine and maybe it was just my poor attempt to bleed it this morning that has given rise to the heater temp variations....

Gonna check behind the engine at the notorious manifold and hoses there and see if anything is apparent!

My P38 behaves exactly the same as this and has done for the last couple of years...

I was really hoping you were on to something with the vapouriser.

Pretty sure it's a HG on mine.

kooky_guy said:

My P38 behaves exactly the same as this and has done for the last couple of years...

I was really hoping you were on to something with the vapouriser.

Pretty sure it's a HG on mine.

Click to expand...

The amount of pressure was no where near as much as it has been, but after sitting for 12 hours+ I wouldn't have thought there would be any pressure....

One thing is good, means there is no leaks as it hold pressure!!!!

Just something is causing an air lock and/or pressure.

Could it be still water in the engine block turning to steam...still water caused by weak pump flow??

Water pump seems capable of moving water as witnessed by the weep hole and bleed screw on the tank!