HGF wrongly diagnosed

Mcfi5dhc

Yes, it is an MG before you ask!

Two years ago my MGZR had HGF shortly after having been converted to LPG - I have no problem with the diagnosis then, it was caused by leaking radiator, and my lack of maintenance.

Fast forward 15 months, car smoking terribly out the back on startup, losing coolant, performance crap, but not getting hot, no mayo in oil cap, but I'm suspecting HGF again.

Take back to the same garage - get the dreaded HGF diagnosis pretty quick, and huge estimated bill. Pay £50ish for the diagnosis, but refuse the repair as decide not economically worth repairing.

Speak to brother-in-law who is handy with cars, but not a mechanic, and he thinks the head gasket is ok, but the inlet manifold is leaking. He repairs that for £20ish.

Performance back up to normal levels again. 320 miles per tank of LPG (same as the time when LPG was originally fitted), which costs about £23 a go, which I think is pretty good.

I give it a month and contact the garage, and ask for a refund for the misdiagnosis - they refuse, and do another diagnosis on the car again (for free) and again say the head gasket has definitely gone.

Fast forward another 9 months to now. I have not topped up the coolant at all since BIL changed inlet manifold gasket. I'm still getting 320 miles per tank minimum (unless I thrash it). No overheating, no problems at all - have done more than 10,000 miles with alleged HGF!


My questions for you are (and by the way, I am delibrately avoiding the MG forums, as I know the garage lurk on there, and I want to be prepared before I contact them):

• Is it possible to get similar mileage from a tank after HGF?
• Is it possible to do 10k with HGF even its minor?
• Is it possible to do 10k with HGF and not top up water at all
• Can LPG give a false HGF reading? #
• Is it worth asking for a refund again?

# The test they did was screw some wierd device with purple liquid in it to the top of the engine. The purple liquid changed colour (which I didn't witness)

Thanks gurus

somech

they did a combustion leak test which detects exhaust gas in the cooling system (is really a food dye) if it changes colour then it head gasket time.
as its been a month since the garage diagnosed it you've no chance of a refund.
lpg would make no difference to diagnosis
what did bil do to inlet manifold????

cheekychappy

Just don't go there again. Get your BIL to fix it in future. Sounds like he knows his onions.

catflea

Mcfi5dhc wrote: »

• Is it possible to get similar mileage from a tank after HGF?
• Is it possible to do 10k with HGF even its minor?
• Is it possible to do 10k with HGF and not top up water at all
• Can LPG give a false HGF reading? #
• Is it worth asking for a refund again?

• You should get identical MPG to pre failure if you've had HGF done, assuming no other changes (or the "saver shim" bleugh!)
• It might be possible, but certainly not advisable
• Highly Highly unlikely
• Should make no difference
• Wouldn't bother, cut your losses

Incidentally, if exhaust gasses get into the coolant they will be there for a long long time (i.e until the system is drained and totally flushed through) so totally possible to have a mis-diagnosis based on that.

I had suspected HGF on my 114gta - turned out to be an inlet leak too - didn't realise it till I had the head off though :rotfl:

steveo3002

doubt you will get the refund

the bro inlaw sounds more clued up ..use him instead , and bad mouth the garage to everyone you can

with rovers most people are going to say head gasket without lifting the bonnet

Mcfi5dhc

Thanks all for your replies

Yes, BIL is way more clued up than the garage!

somech - I think you misinterpreted my OP - nine months ago they detected my 2nd HGF and I haven't had it fixed, and have done 10k since. So my arguement (if I can be bothered going back to the garage) would be that they diagnosed the 2nd one incorrectly, and I never actually had one.

Bil just replaced a rubber/neoprene gasket (which looks like this -o-o-o-o-) - only cost a few quid.

Its a shame really, cos they seem a very professional outfit, but have lost complete faith in them over this. Especially bad as it a Rover garage who you would have thought specialise in this

catflea

Yeah, that'll be the inlet manifold gasket. Not a paticurly hard job, but a little awkwarx

somech

Mcfi5dhc wrote: »

Thanks all for your replies

Yes, BIL is way more clued up than the garage!

somech - I think you misinterpreted my OP - nine months ago they detected my 2nd HGF and I haven't had it fixed, and have done 10k since. So my arguement (if I can be bothered going back to the garage) would be that they diagnosed the 2nd one incorrectly, and I never actually had one.

Bil just replaced a rubber/neoprene gasket (which looks like this -o-o-o-o-) - only cost a few quid.

Its a shame really, cos they seem a very professional outfit, but have lost complete faith in them over this. Especially bad as it a Rover garage who you would have thought specialise in this

the problem is with rovers is that being so known for head gaskets some mechanics get lazy and assume the gaskets failed without looking at it properly.
put it down to experience not all shiny garages are good

catflea

I've made that point a fair few times on here and normally get slated for it. So cheers for that :beer: