CNG leak into cooling system

[Rparker]

OK. I'm new to this and I'm not a mechanic, so I hope this makes sense.
I have a 2000 crown vic cng only with 85,000 miles. I have driven the car about 1,400 miles without any problems. A couple of weeks ago while idling, the coolant blew out of the reservoir cap. I took the car to my mechanic and he has a theory that somehow the cng is leaking into the cooling system and building pressure. I have searched the forum to see if anyone else has had this problem and can't find anything. The cng tech at the dealer seems to think that the pressure regulator needs to be replaced.
Any thoughts? And if that is the case is there someone in Utah that can do the replacement for less than what I'm sure a dealer will charge?

Thanks,
Randy

[Lancer Automotive Group]

Re: CNG leak into cooling system

Give Todd a call at Lancer Automotive he may be able to help you out. 801-268-8863

[freedml]

Re: CNG leak into cooling system

It's hard to imagine that a bad fuel pressure regulator would allow gas to get into the coolant system. I would first look for a blown head gasket which in any kind of car could open a path for engine gases to get into the coolant system.

[hoofnit]

Re: CNG leak into cooling system

I have a similar, but opposite problem on antifreeze around the CNG. There is a device around the CNG filter (left rear tire) that pumps the coolant around a bowl that the CNG flows through. I have a coolant leak and minor CNG leak there. Might it be possible you have a free flow between the CNG and coolant systems there?

[larrycng]

Re: CNG leak into cooling system

Where can coolant come in contact with cng? The first place to look is the High pressure regulator. Coolant that keeps the regulator warm is at much lower pressure than the CNG. If I remember there is a plug in bottom of the regulator that can be seen when the coolant bowel is removed, and I thing there is an "O" under it (Not serviced separatly or for uninitated) other wise there is crack some place requiring a new regulator.

External leaks can happen on Ford (ITT conoflow) it is either the plastic housing that warps, or the "O" ring that seals the coolant bowel to the main housing.

The only other place would be in the intake manifold and that is highly unlikely

Back to basics, was the cooling system pressure checked? Did someone (and very carefully) use a 4 or 5 gas analyzer to look for HC in the cooling system? (suck coolant and the anaylzer is history) Or did someone run a dye check? A head gasket would be a good bett as someone mentioned


Larrycng

[Rparker]

Re: CNG leak into cooling system

Just a follow up. The pressure builds in the coolant system whent he engine is not running. So even with a cold engine I can hear a "gurgling" sound and pressure will build in the reservoir. I can open the cap and release the pressure and ten minutes later without running a cold engine the pressure is built back up.
The car ran great last night on the freeway for 30 minutes and then this morning during a 3 mile trip it blew out the cap.

[CraziFuzzy]

Re: CNG leak into cooling system

This does sound like a problem in the regulator. Because of the way the regulator is jacketed in the coolant (the bowl part), a leak in the regulator would cause gas to leak into the coolant. Sounds like a rebuild/replacement is in order. Did you contact Lancer up above? that's probably what he was going to suggest, and probably help out with.

[Rparker]

Re: CNG leak into cooling system

I took the car to David Johns in Provo last night and I'm expecting his assesment/estimate today sometime. I may then call Lancer to get a competetive bid before I make a decision.

Thanks everyone.

[Kevin Fern]

Re: CNG leak into cooling system

This can happen on the older ITT conoflow regulators. Under the coolant bowl, there is a seal which can leak, I have seen this happen a few times, the only way to fix it, is to replace the regulator. When you order a new regulator make sure that it comes with a metal coolant bowl, if not it will end up leaking coolant.

[Rparker]

Re: CNG leak into cooling system

What is the cost for a new regulator with the metal bowl? How difficult is it to replace with the help of a good mechanic?
My fear is that this is going to be very expensive i.e. $1,500+ and I'm trying to get it done as economically as possible.
Thanks.

[larrycng]

Re: CNG leak into cooling system

If you have not had training or had one appart, dont mess with the regulators. It is not a hard job, but you need to make sure the pressure are set correctly. You need a good gauge and if you really must do it make sure the last turn of the screw is in the clockwise direction (pressure increasing). Make sure you re-seal the adjusting screw to keep dirt and curious finguers out.

Larrycng

[Rparker]

Re: CNG leak into cooling system

I had two different estimates come in today with the regulator at $3,600. I can't justify spending that much on a repair, but I have only had the car for a month, so it doesn't do me any good to try and sell it. I am looking for any alternative. Can the regulator be re-built? Is there an aftermarket regulator? Is there another model year regulator that could be made to work? Where might I find a used part? Any tips are appreciated.

[Lancer Automotive Group]

Re: CNG leak into cooling system

Randy,

We have tracked down the company who manufactures that regulator for ford and hoping we can get it direct, is that a model number on the regulator so we can match it up with what units are available.

They are closed on weekends so will have to contact them on Monday.

[Rparker]

Re: CNG leak into cooling system

I'll see if I can get the number from it this weekend.

[Lancer Automotive Group]

Re: CNG leak into cooling system

Randy,

I have some information for you on your regulator but think we have your phone number wrong. Please give us a call at 801-268-8863