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MG MGB Technical - Have I blown my head gasket?????

Hi Guys.....

I have to admit to doing a REALLY, REALLY stupid thing today, and am concerned I have casued my much-loved GT LE some harm.

It's been running a wee bit too warm lately, so I decided to flush out the cooling system. I filled with Radflush, set it to idle at about 1500rpm and thought I'd pop inddors for a minute or two.... yes, I know I did a stupid thing leaving it, but then it's never overheated before.

Well, I popped inside for 15 minutes: when I came back out, the temp gauge was jammed against the top stop, and the expansion tank was kicking out water like a hosepipe. The engine was starting to run rough. I switched off immediately (obviously); it was REALLY boiling. It can't have been boiling for more than 5 minutes though, and there was plenty of water left.

When it was cool I refilled, changed thermostat etc. When I restarted, the original cooling problem was solved: no overheating or warm running, electric fan switched in and out OK. There's no water in the oil, no white smoke.... I took it for a 20 minute drive, it seemed fine....

SO: is it possible that I've done damage? Will a possible head gasket failure show up later?? Could I have been more of an idiot???

I would very much welcome some opinions!!

Cheers

Bruce
(idiot)
B. Mann

Someone once told me you can run a B series block for five mins without water must say i have never tried it but if you go into the bbs archives on this site i am sure you will find some info
Richard H
UK
Richard H

You're probably OK, but be safe and watch your coolant level to make sure you don't have any slow leaks. These engines can take a lot of abuse, I've overheated several times and no damage done.
R. L Carleen

No oil in the coolant? Compression OK?
...seems like you've dodged a bullet...but keep an extra-sharp eye on everything for a few weeks.

Actually, my experience with these engines seem
to indicate that they are more robust than they are
given credit for - shy of punishing them with abuse,
or neglect, or installing a lesser-quality component
(ie: head gasket).

I've pegged the temp needle on "H" a few times
while creeping along in agonizing highway jams
during hot California summers - without blowing
up, or cracking, or splitting anything (...knock on
wood!).

I'm not a big fan of radiator flushes as they tend to
strip away any protective lube that a good
anti-freeze provides - this is especially critical
to the life of the water pump shaft O-ring seal.

Over-cooking the engine in boiling steam probably
wasn't doing this O-ring seal any favors, either.

I would monitor the water pump for leakage at the
pump shaft for the next few weeks-months.

I flush the system, with the engine off (and cold)
using a garden hose and copious amounts of
water - only. Then refill with anti-freeze and water.
Doing this regularly makes using a rad flush
mostly unnecessary.
Daniel Wong

Bruce. I had a similar problem with the rebuild of the engine for my daughter's car. It blew its second core/freeze/welch plug about a quarter mile from home and blew the coolant out. My case, I suspect, was more severe than yours--my temp gauge only went up to about 7/8 of the max because there was not coolant in the cylinder head.

Contacted several of my friends who have a great deal more experience than I. All recommended replacing the core plug, noted that they have been having some problems with undersized Rover core plug, offered their suggestions for securing the plugs and opined that I should refill the cooling system and drive the car to see if any damage had occurred before tearing the engine apart.

The cylinder head had gotten up to 327 deg F, measured with an infa-red thermometer. It has been running as strong as ever and seems not to have suffered any damage.

I would suggest to you that you drive the car and see what happens. If a problem has developed, I would expect it to make itself evident soon. As the others have mentioned, these engines seem to be quite robust and will tolerate more abuse than some of the more modern engines. Les
Les Bengtson

Thanks very much Guys -

This has reassured me a lot: I always knew these were robust engineS!!

I'll keep an eye on it, but hopefull I've been lucky....

Best wishes
Bruce
B. Mann 1

Bruce,
I would retorque the head.
Leland Bradley

This thread was discussed between 03/09/2004 and 04/09/2004

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