The Triumph Dolomite Club - Discussion Forum

My 1300fwd suffers with a on-going problem of overheating!
I have had the radiator re-cored and fitted an electric fan. After a run of about 5 miles and parked with engine switched off, the expansion bottle will over-flow with boiling water. After about 40 miles the bottle is empty! No signs of leakage, new distributer fitted and timing triple checked, MGB tempreture gauge fitted and averages 190 - 220 degrees - the existing gauge always reads just below hot, just been through MOT so no brakes binding, very poor getting up hills.
Am I right to think the head gasket has gone?
Appreciate any thoughts on the subject.
Pete

Sounds very much like it; have you done a compression test?

I've moved the thread here because it is a technical question.

Never had the need nor desire to use these, even on the K. The heads on an OHV are relatively easy to pull so I'd just pull the head replace the gasket, that way you know you have have eliminated a problem.

The other thing is have you checked your expansion tank cap?

Are you sure the bottle and cap are holding pressure? If it cant pressurise it will lose from the overflow and gush out when switched off as you describe (pressure and temp rise slightly after the pump stops turning)
another cheap test is run the car til warm and quickly whip the plugs out and look for vapour coming out of the plug holes, which could indicate water in that pot. Plug colour may have a tinge of your antifreeze colour too.

Tony

Worth checking/removing/replacing the thermostat as well, before ripping the head off.

Besides the lack of power climbing hills, are there any other symptoms like missfiring, difficult turnover at startup, signs of water in the oil (or vice versa)? Your normal running temperature is way in excess of what is ACTUALLY normal!
I dislike to suggest this and I know it's an iron headed car (so a less likely possibility) but your listed symptoms so far closely resemble those of a 1500 MkI Cortina (also with an iron head) that I once owned. It, like yours, was driveable for shortish runs so I ignored it for ages, having removed the thermostat entirely and flushed the cooling system to no discernible result. When I finally got fed up and pulled the head off, it had a large crack from the No3 cylinder combustion chamber to the adjacent water gallery. In those days, a second hand head at £5 from a scrapyard, plus a new head gasket cured it completely!

Steve

possible airlock?? given it boils so quick??

Start with basics, timing and mixture

Then move on to checking cooling system

Your overflow bottle isn't sealed in a 1300, the level will vary.

Thank you all for your constructive comments.
I am going to go through all your ideas over the next few days and will report back then.
Thanks again
Pete

Hi All,
Have checked:
Compression Test: 1-4 cylinders range from 105-115psi so seems ok to me.
Plug condition: Good and normal. Gap slightly big, so cleaned and reset.
New distributer fitted about 500 miles ago to eliminate overheating and improve performance.
Timing is about right. Not easy on 1300, but through road test adjustment I think it is about right.
Took thermostat out and back flushed system, water clear. Did not replace thermostat.
The water pump was replaced about 1 year ago.
Bled the system with valve on top at rear of head to ensure no air lock.
The oil level is constant and shows no signs of water.
Took car for a junction run at 70mph on M42 and ran normal, but normal road running with hills, the tempreture reached 212 degrees and when I got home the expansion bottle was overflowing.
Seems like the radiator is not cooling properly. I had the radiator re-cored last year because I thought it was blocked, which was confirmed when they took it apart. How can I check it is not blocked again, or that the core was not blocked during soldering?
Appreciate your thoughts.
Pete

You're not far from me Pete, could you bring it up to mine for a look? (Highley, South Shropshire) I don't have a pukka 1300 rad, but I have a 1500 Dolomite one we could probably jury rig to fit for test.

A crack in the head will not always show a drop in compression but could still be the cause. best to eliminate every other possibility first though!

Steve

Or alternatively, have a wander to Coventry, for advice, sympathy, and 1300 bits

If this were a slant 4, I'd be checking to see if the water pump impeller was slipping on the shaft. You say your pump was replaced about a year ago; was it a reputable supplier? Can the impeller fail on a 1300 pump? What proof do you have that the coolant is circulating properly?

I have had a similar water loss issue on my 1850 Auto this weekend.

Coming back from the Isle of Wight the temp gauge was going up, topped it up with ¼ litre of water but 7 miles later the same thing, and again 7 miles later.

I stopped at Liphook services and could find no signs of a leak, all the hoses are new and so is the radiator, no weeping from the water pump slot either.

I called the AA who pressure tested it, again nothing untoward was found. The AA concluded that it was probably the early stages of head gasket failure.

So I look forward to that job like a hole in the head.