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MG MGB Technical - Cooling Woes

First of all, let me just say that you guys (and ladies) are great. This is the most helpful sight I've found for my '77 B. My first question was answered (I think) in a previous thread. I'm going with the Weber 32/36 DGV carb with Cannon Header kit. Great prices at Brit-Tek. I believe I also have a crack in the exhaust manifold. Will this header easily attach to just about any exhaust set-up?
My main concern after that is overheating problems. I'm going to attempt to drive this car (on the interstate) for over 250 miles, that said, the longest I've gone at one time is 40 miles. I've flushed the cooling system and replaced the thermo. It still tends to get "hot" on the highways. Any suggestions? Any other advice before making a long-road trip would be appreciated too?! Thanks in advance-
Kyle

Kyle. These cars do tend to run somewhat hotter in summer than most people are used to. With a good cooling system, flushed, 25%AF-75% demineralized/distilled water, a working thermostat, new hoses, new expansion tank pressure cap, and both of the electric fans working properly, you should have no problems. On my cars, the temperature gauge will get towards the upper end of the scale--somewhere between 3/4th and the top of the scale. It will tend to go almost to the top of the scale in stop and go highway driving. But, none of them have ever boiled over.

Do not discount the fact the gauge may be reading incorrectly. Had a new owner bring his 77 over last week for a similar problem. The dash gauge was reading 3/4 of the way to hot. We used an infared thermometer on the cylinder head and it measured 187 degrees. Certainly nothing to worry about when the outside temps are above 90 deg. This will be the first summer I will have had the I-R thermometer to actually measure what the engines are running at and to check the coolant flow, so I expect to have a better understanding of these systems at the end of summer than I do currently. However, the old, "If it's not boiling over, don't worry about it" concept has worked well for most of us for many years.

If you are really concerned that the engine is running too hot, drop a few drops of water on the cylinder head near the thermostat housing. If they sizzle, the head is above the boiling point of water and you have a problem. If they do not sizzle, no worries. Les
Les Bengtson

Because the system is sealed and pumped it has both a static and dynamic head.Both of these raise the boiling point so water could boil on the outside , but not the inside . I do agree that once you get to this point , you have a cooling problem .
S Best

Kyle,
Do you B have electric fans I say fans because some of these cars came with one fan, in Canada for sure I guess the brits believed it never got hot here. My car always ran a bit on the hot side in heavy traffic and hot days until i installed an extra fan. My car 1980 was wired and ready for the extra fan . I found a fan on e-bay for about 1/3 the price and the problem was solved
Cec

Cec

Kyle - What do you mean when you say it gets "Hot" on the highway. If the coolant is not boiling (steam and coolant spewing out) or the engine is not missing, the car is not overheating. Since you have a 77 MGB with a electrical temperature gauge and sensor, you may well have a sensor that is lying to you. See the thread, 1973 MGB Over Heating by Robert Browning about half way down the list on this BBS. Be sure to read down to the solution and what Robert found regarding the sensors. Your's could be a similiar problem. Good luck - Dave
David DuBois

This thread was discussed between 14/05/2004 and 15/05/2004

MG MGB Technical index

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