Just thought I would attach a previous post to this new thread so that anyone doing a search (in the future) for an LPG conversion can read this thread and carry out this modification. Please also see my other previous posts.
This is not meant to frighten anyone from doing the conversion but just carry out a preventative step to over come any potential increases in temp that the LPG can cause, this incident is most probably not caused by the LPG conversion but it may not of helped.
Re: Cooling system over pressureing 4.4 V8 L322
I have had the car tested today by my garrage, putting a large tube with 2 lots of coloured solution, on my water expansion tank. The theory is that if there are any exhaust gases getting into my cooling system then they will bubble through and change colour. Mine changed colour ! But not for ages until the car was well hot about 105-107 degrees on the diagnostics. Indicating that there is a start of a problem with the head gasket but it appears to only happen when the car gets to a critical temp, ie really hot and things expand enough to seap exhaust gases into the cooling system which then causes pressure problems.
What I have done to hopefully help/ iliminate / prolong failure, is to wire my electronic thermastat to ground, so that when ever the car is started the heated thermastat starts to warm up. How it normally works is that an ignition live is fed to one side of the thermastat heater and the other side goes to your ECU. When the ECU wants the thermastat to open fully because of it detecting big loads (towering or driving fast) it puts it down to ground to pre empt the impending extra heat generated from these activity's.
My mod means the result is that when the car is upto full heat it is running at 90 degrees instead of 105 degrees and isn't over pressured. (the design is to control between 80-103) with the electronic thermastat over riding and coming on at 113 degrees if the ECU hasn't already asked it to open.
I could have just removed the thermastat but this would have made the car take longer to heat up in the morning and as the electronic thermastat is only assisting the mechanical thermastat this wouldn't open until the cooling water is hot.
The temperature guage doesn't change as it isn't that sensitive. It will show exactly half way when it is between 80-103 degrees.
I would say that maybe the LPG conversion may not of helped as it does run a little hotter but could never know for sure. The 75000 miles and a possible over heat problem that happened prior to my ownership seams more plausable.
I would recommend anyone doing an LPG conversion on a L322 4.4 V8to also carry out this modification as preventitive maintenance to stop the car running any hotter than it needs to. The job takes 15 mins, you need to remove the top engine cover (4 allen keys bolts) take the plastic cover off the left hand wiring box, (this is about 1 foot long and is located over the left bank). Remove the plug/connector from the heated thermastat, confirm it has 2 wires going to it, one is red/blue 12V+ (ign live) the other is brown/white and goes to the ecu. Trace back these wires into the wiring box, scrape back the insulation on the brown/white wire (think there could be more than 1) and test with a multi meter that you have the correct one. Happy cut it, then check again with the multimeter that between the plug and the snipped wire you have continuety. Now connect this brown/white wire from the plug to a ground, I used a bolt in the engine bay top left where the brake resevour is. Get your multimeter check you now have 12 volts at your plug (when the ignition is on.) Put it all back together, the only way you can now check how hot your engine is running, is by sticking it on the diagnostic machine.
Think about the theory, does it make sense ? I believe this is the way forward to prevent an expensive job. I love my car, and really don't want to get rid of it or pay the thousands of pounds for head gasket repairs so maybe just maybe this will help ? I will now monitor. What I do know is that previously my car was running about 108 degrees and very pressured up on all hoses. Now running at 90 degrees and pressure is dramatically reduced, if the pressure is reduced this will help radiator, pump and hooses going as there is less strain on them.
I hope people read this and it helps...............................Adam
This is not meant to frighten anyone from doing the conversion but just carry out a preventative step to over come any potential increases in temp that the LPG can cause, this incident is most probably not caused by the LPG conversion but it may not of helped.
Re: Cooling system over pressureing 4.4 V8 L322
I have had the car tested today by my garrage, putting a large tube with 2 lots of coloured solution, on my water expansion tank. The theory is that if there are any exhaust gases getting into my cooling system then they will bubble through and change colour. Mine changed colour ! But not for ages until the car was well hot about 105-107 degrees on the diagnostics. Indicating that there is a start of a problem with the head gasket but it appears to only happen when the car gets to a critical temp, ie really hot and things expand enough to seap exhaust gases into the cooling system which then causes pressure problems.
What I have done to hopefully help/ iliminate / prolong failure, is to wire my electronic thermastat to ground, so that when ever the car is started the heated thermastat starts to warm up. How it normally works is that an ignition live is fed to one side of the thermastat heater and the other side goes to your ECU. When the ECU wants the thermastat to open fully because of it detecting big loads (towering or driving fast) it puts it down to ground to pre empt the impending extra heat generated from these activity's.
My mod means the result is that when the car is upto full heat it is running at 90 degrees instead of 105 degrees and isn't over pressured. (the design is to control between 80-103) with the electronic thermastat over riding and coming on at 113 degrees if the ECU hasn't already asked it to open.
I could have just removed the thermastat but this would have made the car take longer to heat up in the morning and as the electronic thermastat is only assisting the mechanical thermastat this wouldn't open until the cooling water is hot.
The temperature guage doesn't change as it isn't that sensitive. It will show exactly half way when it is between 80-103 degrees.
I would say that maybe the LPG conversion may not of helped as it does run a little hotter but could never know for sure. The 75000 miles and a possible over heat problem that happened prior to my ownership seams more plausable.
I would recommend anyone doing an LPG conversion on a L322 4.4 V8to also carry out this modification as preventitive maintenance to stop the car running any hotter than it needs to. The job takes 15 mins, you need to remove the top engine cover (4 allen keys bolts) take the plastic cover off the left hand wiring box, (this is about 1 foot long and is located over the left bank). Remove the plug/connector from the heated thermastat, confirm it has 2 wires going to it, one is red/blue 12V+ (ign live) the other is brown/white and goes to the ecu. Trace back these wires into the wiring box, scrape back the insulation on the brown/white wire (think there could be more than 1) and test with a multi meter that you have the correct one. Happy cut it, then check again with the multimeter that between the plug and the snipped wire you have continuety. Now connect this brown/white wire from the plug to a ground, I used a bolt in the engine bay top left where the brake resevour is. Get your multimeter check you now have 12 volts at your plug (when the ignition is on.) Put it all back together, the only way you can now check how hot your engine is running, is by sticking it on the diagnostic machine.
Think about the theory, does it make sense ? I believe this is the way forward to prevent an expensive job. I love my car, and really don't want to get rid of it or pay the thousands of pounds for head gasket repairs so maybe just maybe this will help ? I will now monitor. What I do know is that previously my car was running about 108 degrees and very pressured up on all hoses. Now running at 90 degrees and pressure is dramatically reduced, if the pressure is reduced this will help radiator, pump and hooses going as there is less strain on them.
I hope people read this and it helps...............................Adam
