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MG MGA - Heater no heat...here's why

Now, don't get mad at me when I say that the temperatures dropped way down low in the low 50's here in Santa Barbara and my daughter complained about the cold in her 57 1500. I told her to toughen up and that the MGA heater kicks out plenty of heat. Then I drove her car and realized something was wrong. Here's what I found


David Holmes

Not an uncommon problem. I've seen that exact same thing on my '65 MGB. About the only solution is to replace the heater valve.

Cheers - Dennis
D L Rainey

Yuck. What the heck? The entire valve was plugged with a sandy goop as was the port from the head. I used Bob Munchauser's web site and took the valve apart and cleaned it up and while I was at it added a couple of shims to the shut off valve. I had the original 1957 valve in a box of spares and a spare gasket so I installed the original valve which works fine. I'll use the modified repro valve on my 1600 and then do the same improvement on the one I remove.


David Holmes

Yes, you definitely need a heater when the temps get down into the low 50s. I'll bet you California folks even consider heavy coats at those temps! ;-)
You'll believe her next time she tells you there's something wrong though won't you. Hope she enjoys her warm MGA this year.
Bill Young

Someone should check on Del Rawlins up in Alaska. The tempurature there has been -60 degrees for a week and a half. Must be fun for him driving around in his MGA with the top down.
Gordon Harrison

Bill, you bet. She's got my attention now. Heavy coats? no one owns heavy coats in Santa Barbara. A windbreaker is all that is needed on most drives in the winter.
David Holmes

David. Please be aware that the build up you see on the valve and in the cylinder head may, also, be present in the rest of the block. This type of build up may respond to a cooling system flush, or it may not. There are some "heavy duty" cooling system flushes which are/were available. They should be avoided. The one time I tried one of them, it ate the head gasket quite severely.

The best way to remove all of this type of thing, which builds up, especially, in the area of cylinder four, is to remove the core plugs and scrape out as much as possible, using a vacuum cleaner to pull out the crud after it has been loosened. I have found severe fouling in engines that I have torn apart for rebuild. Removing the core plugs and "hot tanking" the block used to remove this type of thing (along with the cam bearings and the engine tag, if they were not removed first). Modern hot tanks do not seem to do this very well. My last block was "hot tanked" over a weekend and still had large amounts of blockage in the cooling passages.

Les
Les Bengtson

> Heavy coats? no one owns heavy coats in Santa Barbara.

Off topic, but I'm reminded of a time that my wife and I were visiting her folks in Florida. At the time, they were searching for a winter residence and we went with them to look at a particular condo. On entering, my wife quickly scanned the foyer and proclaimed, "Hmmm, there's no where to put your coat and boots". The real estate agent gave her a puzzled look for a moment then smailed and said, "Oh, you're Canadians. We don't have coats and boots here in Florida".
Andy Bounsall

Many decades past engine coolant might be alcohol in winter and water in summer. In mild non-freezing climates (of for cars stored indoors in cold weather) it might be water all year round. Plain water for coolant leads to copious amounts of rust in iron engines. The sediment mostly settles in the bottom of the water jacket in the engine block. Hot tanking may clean most of the rest of the water jacket, but it will not remove thick accumulation of sediment in the bottom.

When the engine is stripped to the bare block for machining, the sediment layer should be mechanically removed before hot tanking. Remove all core plugs. Use a 1/8-inch steel rod held in vice grips, poking downward through all of the water passage holes in top of block to probe vigorously at sediment in the bottom, thereby breaking the sediment up into large flakes and coarse sand. Then stand the bock on end nose down and dump the trash out the front through the water pump port. This could be half an hour of hard work. Last time I did this with an old engine I got two pounds of sediment out of it.
Barney Gaylord

>Someone should check on Del Rawlins up in Alaska. The
>temperature there has been -60 degrees for a week and a
>half. Must be fun for him driving around in his MGA
>with the top down.

It's gotten down to -20 here in Anchorage, and I work outdoors. The MGA is torn apart in the garage, and needs me to get back to work on it. About the coldest I have driven it at was +20F, top down. I haven't felt the need to repeat that experience. And with the lack of summer that we had last year, I haven't bothered putting the soft top on the Jeep in the last couple of years, just left the hardtop on. I hope I remembered to plug it in last night.
Del Rawlins

I recently pulled my heater valve off the engine during the restoration and found the same thing, completely clogged. But mine was a white oxide type material and was hard as a rock. I also found it on the aluminum thermostat housing and a little on the water pump. All I can figure is someone put in an antifreeze that wasn't compatible with aluminum in the system. The passages in the block look fine.
DAR Dave Rosato

I had to mechanically clean the passages in the block many years ago when I found the heater not working. With the head removed, I was able to clean it pretty well with a long thin screwdriver and some wire.

Del, I had my "A" out in the driveway a couple of weeks ago, while I cleaned up enough to also get my Jeep inside. In spite of the cold, I was tempted to take her out for a short drive, but was saved when I remembered that I had suspended the insurance for the winter! I think that I preferred the minus 20 to the wind and rain we have this week.

Ken
k v morton

This thread was discussed between 08/01/2009 and 17/01/2009

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