Top of Mulholland with an broken midget

[tykluss18]

It's all fun and games until your buddy comes in an American car and cracks jokes.

Help me out here if you can guys,

Last week I bought a bypass hose for the 1275 A-series motor in my Midget to replace the blown bypass hose, that replaced the blown bypass hose that came with the car. I had just gotten a new set of tires and flushed the cooling system in preparation for the labor day fun run. I was testing the tires on Mulholland when I got stuck past Las Virgines. The mixture Im running is 2 pints Prestone, 4 oz. Redline Water Wetter and rest distilled water (~ 5 pints.)

Here's what seems to happen: the car runs fine, in fact the cooling system seems to be working great, running right around "N." I have a Smiths dual gauge to show my water temp (more accurate when I tap on the glass. ) Like this:



Now when my driving begins to become a little more "spirited," it will run about halfway between normal and the white area. Then what i'm guessing happens is the bypass hose fails, and then i quickly lose the coolant mixture. The temperature begins to rapidly climb and I hear the hissing. When I pull over and there is a vertical split in the bypass hose, and no other obvious leaks or breaks. Again, this has happened twice...

So my question to you all is why does my bypass hose keep failing? I have a 15lb. cap on the expansion tank (workshop manual recommended is 15lb.) and though I haven't taken it out to inspect it, my thermostat seems to be working properly, though I don't know at what temperature it kicks open.

Has anybody had this problem or a similar problem before? Any help is appreciated!

Thanks,

Tyson


I will admit that it was almost unfair that this was my view and my shade tree while waiting for help

[Fifty Six MGA]

I say this in the warmest, nicest way I can.

Welcome.

[tykluss18]

I say this in the warmest, nicest way I can.

Welcome.

Hahaha thanks!

If only I could reject your welcome and have it go away!

[tannyo]

This thread suggests using regular heater or silicon hose to replace the thin bypass hose. Unfortunately, it looks like you have to take off the water pump and replace the gasket to replace the bypass hose. Unless you use an accordion hose.

I looked at a picture of the bypass hose and it has a seam lengthwise on the hose which could be a failure point, bad design or there's a batch of bad bypass hoses out there.

Why don't you try an accordion hose and see how it works? Should be a lot easier to put on as you don't have to remove the water pump and no seam to split.

Tanny

[HealeyBN7]

I have a box of hose cutoffs the were left over from plumbing the Lotus, Peerless and Warwick systems. You are welcome to come over and dig around to find one the fits.

Dean

[Steve Simmons]

Just go buy a piece of Vulcoflex hose in the right diameter and be done with it. You don't need a flex hose there because the two pieces are locked together. The Vulcoflex will outlast the engine. It isn't a big job to pull the water pump, clean and renew the gasket, and bolt it back on. You have all weekend!

[tannyo]

Are you running a stack pressure radiator cap?

[tykluss18]

Dad and I were able to get a 1/2" coolant hose piece to replace the molded bypass hose to solve the problem. And tanny, I did replace the radiator cap with a 16 lb rated cap i got from pep boys. The stock recommendation is 15lb. so i figured this would suffice. At this point I believe that the moss hoses were faulty!

[VWNate1]

Still no recurrances ? .

In this beastly heat my BMC 1500 C.C. engine almost reached 195* F to - day .

It was 103* F in Pasadena .

[tykluss18]

The new hose hasn't busted but it has gotten pretty hot a couple times since then. I did determine that once the needle hits the white area it is at about 220 degrees on the thermostat housing. Infrared thermometers are great!

I'm looking into come aluminum radiator options now to help out the cooling.

Speaking of which, has anybody ever heard of a radiator company called Champion? Anybody use their products?

[Fifty Six MGA]

My temperature used to get pretty hot, which was either the result of a failing head gasket, or the cause of it. When I replaced the gasket and reworked the head (new valves, etc), I also added a shroud to the radiator. Just some thoughts.

My car can now drive hard, for extended periods, in hot weather, and the temp never breaks 190. I had planned on replacing the radiator, but ended up my radiator was fine.

Geoff

[tykluss18]

I can try a shroud, that is a good idea...I am considering this Champion radiator because it is only about $200, it is Chinese but the MG experience forums seem to love it as a cost effective stock type replacement.

[Steve Simmons]

Don't be so quick to spend money on an aluminum radiator. All else equal, copper cools better than aluminum, and servicing the copper one you have is more cost effective than replacing with anything new. I would also suspect the efficiency of a cheap aluminum radiator since they typically cost a lot for a quality unit. You might get lucky but then again it may be less efficient than the one you have now. Factory cores are typically very good when in new condition, and have the proper flow rate for the engine. Some may disagree, but that's how I see it.

I would suggest having your radiator boiled out and tested, and replace the thermostat while you're in there. Before installing it again, flush and reverse flush the cooling system several times, including the heater circuit. Also make sure that all seals are in place in the engine bay so that air is not bypassing the radiator as it enters through the grill. This should make a world of difference.

[VWNate1]

What Steve said .

It's worth remembering that in the years before you aquired this vehicle , it prolly sat for a while or , ran plain water in the cooling system , often both and the end result is silted up rust deposits in the nether reigions of the water jacket deep inside the block and cylinder head .

Simple hose flushing like shops & most DIY'ers do , won't addess this .

You need to first clean out the old coolant and then any oily residue by using sudsless detergent ('Shout' or equal) then use a good cleaning agent for a days worth of driving to get the deepest deposits loose ~ I use Citric Acid powder but Prestone's Heavy Duty flush in the yellow plastic bottle , is also Citric Acid based and I am told works well at about 8 X the co$t .

Simply up grading or boiling out the radiator isn't going to help if there's anything else amiss .

Of course you've allready checked and adjusted the vslve gaps and ignition timing as they both play a huge part in how cool or hot your engine runs .