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MG MGF Technical - Urgent help needed - engine problems (long post!)

Greetings one and all. Now i'm not too technically oriented when it comes to car mechanics so i'll do my best to give the diagnostics of the problem.

I recently suffered a HGF on my 96 MPi. With over 80,000 miles on the clock and a badly battered engine due the prior misuse from it's 2 owners i opted for a reconditioned engine with 4,000 miles (a newer model to my old one - unsure of the exact year of manufacture though), courtesy of the MGF centre.

The engine fitting went smoothly and i was advised to take it easy for 200 miles or so, check the water levels and oil daily, and ensure there's no visible leaks. Upon delivery of the car, the difference was remarkably noticeable. The car pulling like nothing I’ve ever felt before, almost as though the old engine was 50% underpowered or something; needless to say, not being able to put my foot down to feel the power at full capacity was slightly doing my head in, but I resisted all temptation and followed my mechanic's instructions explicitly and took it ever so easy.

Some teething problems did occur as i had a faulty washer on the radiator bleed tap which led to some coolant loss, spotted early and thankfully resolved.

Last night after a 20 or so minute drive, i left the car to idle for a few minutes before switching off (as is advised). I got out the car to stretch my legs and that's when i heard some weird noises from the engine bay. The expansion tank and engine sounded like a kettle reaching boiling point. The pressure was so immense that water had actually begun seeping out the expansion tank. On an added note, temperature and oil gauge both read normal.

I had a word with my mechanic who has spent the better part of the afternoon investigating the cause. He seems to think that the radiator cannot deal with the heat and the possible reasons behind this are:

1. Blocked radiator? He's currently stripping it out.
2. Timing of the fan set too high?
3. Faulty expansion tank cap? We've decided to replace it any for safe keeping.
4. ???????

Thermostat has been eliminated as a cause thus far, and luckily no further damage was caused by this mishap. One things for sure though, the engine is heating far faster with the new engine in place than it did before. It use to take the car a good 15 or more minutes to reach normal temperature, but now within 3-5 minutes the gauge quickly moves upwards reaches normal.

Any advice i can pass on from the forum guru's would be most appreciated. I have all the faith in my mechanic but for the first time find him a little baffled by this one.

Cheers all,

John





JW Ioannou

My engine warms up to temperature pretty quickly too - so I don't think that this is anything to be too concerned about at this stage.

Boiling in the expansion cap means that the system is either over pressurised (possible if the fire-rings on the head gaset are not sealing the combustion chambers properly), or under pressurised due to leakage.

If the former, an exhaust gas 'sniffer' - the gas analyser probe used for MoTs in the UK and I guess for your local equivalent - can be used to detect the presence or absence of hydrocarbons in the expansion tank.

Hydrocarbons should not be present. If they are, then I am afraid that the head gasket has failed, and will need replacing.

If absent, then I would look to exclude a cause of pressure loss - the expansion cap being a prime candidate that you are replacing anyway - very sensible.

Check your hoses too - if you've re-used the originals, then there is a good chance of failure in my experience. Old hoses don't like being disturbed, and hate over heating. Odds are that they'll leak and ultimately fail completely. I'd be very tempted to replace them as a precaution.

Regarding overheating - what evidence is there that this has happened? At moments like this, it would be nice to have a reliable temperature gauge!!! Perhaps Testbook can give a better indication as to coolant temperature when you had your steam erruption?
Rob Bell

hello i also recently suffered from hgf for second time. on getting car back from garage last wednesday i was told to watch water level closely (in case of airlocks in cooling system) travelled about 15 miles wednesday and found thursday morning expansion tank needed quarter of a pint to top up to max level went to work and back about 20 miles then checked again thursday evening only to find lost another quarter of a pint toped back up. meanwile i had ordered b&g level sensor http://www.ukmgparts.com/index1.html?o=11440899395578
this kit arrived friday really fast delivery fitted kit saturday afternoon must say the kit is good quality and really easy to fit i would recomend to all mgf drivers to give a little peace of mind.
whilst fitting thought i would have a good check around engine/rad/heater only to find water dripping from flexible hose on engine on closer inspection jubilee clip holding hose was loose and could be moved up and down hose with ease tightened down to hose then went for a long drive everything now seems ok no water loss. i don't think i will be using this local garage again so my advice is if you can check yourself for peace of mind.
d l brown

>> i don't think i will be using this local garage again so my advice is if you can check yourself for peace of mind. <<

From Nottingham it is but a short trip to Goldthorpe and Mr Satur's garage.I'd be tempted to go there.
Pete

ive been to mike satur to fetch my roll hoops http://www.frappr.com/?a=viewphoto&id=761437&pid=1534696 and yes it isn't far i think next time i need work doing it will be with him.
d l brown

John,

I hope your radiator doesn't look like this nine years old from a friend in North Germany.

http://www.mgfcar.de/radiator/radiator.htm
(No joke. Pictures taken a couple of days ago)

Anyway, go for what Rob said, if you are very sure that the radiator fan does what it should. (Check fuse / Relay / ECU sensor)
Dieter

Good grief Dieter!

Luckily my radiator does not look anything like that. Had it replaced last year for a brand new one ;o)

Updates so far as follows:

We've flushed the radiator which did have some dirt in it but not nearly enough to cause a blockage. All the hoses on the engine were checked Rob and just like with Daren, a small drip was spotted on the flexible hose of engine, now replaced with a new jubilee clip. All other hoses in remarkably good nick.

Once the radiator is put back on the car, we'll run another check to see if everything is as it should be. Old expansion tank is still on for the time being with a replacement one at hand. Won't change it until sure that all other possibilities are eliminated... you never know!

Cheers for all the advice everyone. Will keep you posted on developments.

John
JW Ioannou

Holy radiators Batman!!! 8-O

Dieter, that has to be the worst radiator I've ever seen!!!
Rob Bell

Hi John,
where on Cyprus do you live? Were in Larnaca during last week,nice and warm, all soft-tops unfolded despite well over 22deg C. And not a single F to be seen.... / Carl.
Carl

Hi Carl,

Living in the capital of bananaland, Nicosia. You're absolutely right, not a single F in sight. A plague of MX5's and Z3's and 4's, but only a handfull of F's and 1 TF here.

They have a very bad reputation unfortunetly and the dealership here has never helped better the situation whatsover.

The good news is i get stares no matter what, even though most think i drive a BRG MR2... doh!

Despite the warm weather it's still winter here for most. Stupidly enough, tops only come down when the temperature soars to 40+. Ever seen beetroots driving convertibles...? ROFL!






JW Ioannou

Part 1: Frustration!!

This situation is getting increasingly frustrating. I can now confirm that we have checked absolutely EVERYTHING on the engine and for the life of me cannot figure out what's wrong!!!

ECU checked, Fan checked, Radiator flushed/bled checked, Hoses checked, Expansion tank checked, Thermostat check, Sensors checked... ARGHHHHHH!!! And still she boils every single time!

My mechanic has now been forced to contact the MGF centre to see where he "might" have gone wrong when replacing the engine. Things are not looking good for me... Been without a car since early January and it seems there's no end to the problems or the money i'm forced to spend on this ordeal!

Part 2: Some hope in the darkness

Praise the MGF centre for informing my mechanic that there is in fact a 3rd bleed nipple valve on the car which he did not know about. This is pretty much a last resort but the MGFC seems confident that that will solve it. Time will tell. Update to follow...



JW Ioannou

This thread was discussed between 03/04/2006 and 05/04/2006

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