WD45 Has Weird Radiator Overflow Issue

I have a WD45. Been chasing a weird problem since I bought this tractor this summer. The radiator loses antifreeze out the overflow tube but only does it after putting a load on it like after plowing or disking. Won"t do it while brushhogging or othe light work. Has a new 8 PSI cap and new temp gauge from Steiner Tractor. The neck in the radiator looks fine where the cap seats. According to the gauge it doesn"t even run at normal temp until it"s loaded and even then it"s still in the green area and never overheats. Have flushed the cooling system and replaced with 3 1/2 gallons of fresh 60% mix. It had head work done on it before I bought it  but  this tractor has had a ton of problems so who kno knows if they efven bothered to  check the head for flatness etc.. I havn't checked the thermostat, could a missing thermostat cause this? Anyone know of a radiator pressure testor that will work on this tractor?

Thanks.

 First of all , an 8 psi cap is too much, a  4 lb cap is what you need, if you could see the tanks bulge on some of these old radiators  as I do when pressure testing after a repair ,it would suprise you!  Yes , you should run a 180 thermostat, anything less won't burn off condensation, you will sludge your engine oil. Every radiator has a sweet spot that it likes as far as coolant level is concerned, so if you keep adding what has puked out the overflow , it will do it again. Keep an eye on your guage and let it seek its own" happy spot". And  a 50/50 mix has the best level of protection against freezing vs. heat transfer, should be good to at least 25 below.

Maybe it could be a headgasket issue.

Does the radiator cap match the radiator? My WD did that.........turned out I was using a cap for a "shallow neck".  Radiator shop gave me one for "deep neck" (about 1/8" deeper) and the problem went away.

Mine does that too, when plowing or disking, always just thought it to be from having a very full radiator and just slosh over out the overflow tube. Never worried about it, but worth checking it out just to make sure its not more than that.

One check would be to leave the radiator cap off, and get it hot and see if there is air bubblng out of the radiator top tank water. That would be a sign of combustion gasses getting into the cooling system from a head gasket leak.

The top tank is the expansion volume as well as manifold for the radiator's tubes, so you don't need it full. Think about how much water has to expand from when you filled the radiator up to 190F. The top tank needs enough air to accept that expansion and not run the pressure over 4 psi.

Takes 14 quarts cold my spies say.

Babcock steam generator reference says water expands about 4% from 70 to 212. So 14 quarts becomes 4.6 quarts. So you need to compress the air in the top tank from 15 psi (atmospheric pressure) to a maximum of 19 psi. means a reduction in air volume by 15/19 or to 79% of the original volume. That 21% of the tank volume is the .6 quart water volume increase so you need 2.85 quarts of air space minimum, nearly 3/4 gallon.

I think if the air isn't bubbling, you just have the radiator way too full to allow for expansion.

Gerald J.

Cavitation on liners is usually a diesel problem,not a gas problem. With either there is a tendency for oil to show in the radiator and antifreeze in the oil.

Gerald J.

I just got my 45 back together last week.(full blown rebuild...ouch) It was all but at the bottom of the neck with 3 gal coolant.How'd you get 3 1/2 in yours.I think you are OVERFULL !!

The first on line reference that I found that listed coolant for a WD-45 said 14 quarts for gas and 17 for diesel. I didn't see a reference that really knew, like an owner's manual.

Gerald J.

I had the same problem, I put a catch can on so the over flow could be caught, less then a cup was caught in the can after a few months of running the tractor, after that it was ok and never over flowed again.

take all the pressure retaining capability out of the cap then it ill be fine unless compression is getting into it.

Edited by mlpankey - 24 Dec 2010 at 8:37pm