YM2000 Radiator Reservoir Overflow

[Gary2]

I have a YM2000 and the radiator overflow tank continues to fill up after successive warm up / cool down cycles and eventually overflows. I have replaced the radiator cap twice with a 13 Lb cap and continue to have an overflow problem. When mowing this summer my temp gauge only reaches 190 to 210 °F max in Central Florida and I believe the gauge is accurate because I checked it’s full range with a thermometer before installation. At the highest operating temperatures (210 °F with 50/50 Mix) I can see a pulse of air purging every 5 seconds or so from the down tube in the overflow tank. Do you think I have a head or head gasket leak? Any recommendations, thanks Gary

 

[LMTC]

. Do you think I have a head or head gasket leak? Any recommendations, thanks Gary

Yes.

Fix it or get it to someone who can. You only exacerbate the damage to continue using it.

 

[lens12]

It should be sucking the coolant back in the radiator when it cools down. Check for a leaking hose.

 

[BruceR]

(210 °F with 50/50 Mix)

Your YM2000 should also be running a 30/70 mix.

Bruce

 

[lens12]

The 30/70 mix is recommended on models without a waterpump.

 

[Box]

I have a YM2000 and the radiator overflow tank continues to fill up after successive warm up / cool down cycles and eventually overflows. I have replaced the radiator cap twice with a 13 Lb cap and continue to have an overflow problem. When mowing this summer my temp gauge only reaches 190 to 210 °F max in Central Florida and I believe the gauge is accurate because I checked it’s full range with a thermometer before installation. At the highest operating temperatures (210 °F with 50/50 Mix) I can see a pulse of air purging every 5 seconds or so from the down tube in the overflow tank. Do you think I have a head or head gasket leak? Any recommendations, thanks Gary

Gary,

You may have a head gasket leak but before you tear into the engine make sure you check and test everything you can before hand. I have a 1610 that has a similar problem. There is a thred on my issues on TBN if you want to see what I have done so far. There are several post from others in that tread that might help you as well.

I had convinced myself that the head gasket was the issue at first, but after having the head checked and replacing the gasket I am still struggling to figure out the source of the air bubbles. My unit runs good and seems to have plenty of power. Your description of the problem is identical to the issue I have had. I have noticed that if I only fill the over flow bottle to low level mark, I can run the unit for several hours with out over flowing the bottle. I am now rechecking the raidator flow and will soon be replacing the water pump. I suspect I may be sucking air into the system somehow rather than an issue with compression but I still have some tests to preform before I know for sure.

I am strapped for time to work on my tractor right now, but If I come up with any conclusions that I think will help you I will be sure to post them.

Good luck........

Box

 

[rock2610D]

This might be a too simple to mention but I have to. Are you sure the radiator is not too full? IE filling the radiator to the top and then having a resivoir with fluid in it could make the overflow bottle overflow until proper amount of fluid is in system??

Also, contaminated water could be a cause. If any contaminate got into the system it could be hard to get out. IE radon for instance will gass at atmospheric pressure out of water. Some other contaminates may gass only after getting hot creating the bubbles and the appearance of air getting into system, when in fact the fluid is just letting the contaminates excape in gas form??? Try distilled water and antifreeze with the proper amount of anti-cavation fluid, it may work.

Also, some people will put pepper into a radiator to stop a leak. Hopefully this is NOT the case here. I personnally consider any stop leak or pepper a contaminate and a system flush may not get all of it out.





Just a thought.

 

[Gary2]

Thanks for all your responses. I have checked all the hose connections thinking I may have a vacuum break in the line from the reservoir to the radiator and every thing seemed good. I did place a hose clamp on the connection to the radiator several weeks ago. A friend rebuilt my radiator about a year ago and instead of replacing the two tube core he put a three tube core in it. This has given extra cooling capacity and possibly too much as I have to put a board in front of the radiator in the winter. With the extra cooling capacity I have been using a 50:50 mix of distilled water/coolant thinking that would give less cooling and better corrosion protection. That theory may not be right??? The three tube core probably has more water volume and would require more overflow volume.

rock2610D, I have to admit I have been keeping reservoir cold level above the bottom mark when I probably should keep it below the mark and I have also been keeping my radiator full. I have not had this overflow problem until last weekend when I kept the tractor running continuously for 5 or 6 hours.

The motor runs great, always starts on the first crank and I can’t see any residue in the coolant and the motor oil is free of water.

Box, thanks for writing, I may have had the head off by now. Since reading your thread I have ran the tractor for several hot/cool down cycles trying to notice when the air bubbles pulse through the down tube into the overflow bottle and when it doesn’t. So far it appears to happen only when the engine is over 170°F and idling less than 1000 rpm. The bubbles appear several minutes after idling down and go away several minutes after idling back up. I have only tested this at our house in the suburbs and can only mow for a few minutes but I can get the temperature up by placing my winter board in front of the radiator. My situation is similar to yours in that we are about to build on our 2.4 acres so I will have to wait until I am out there with the tractor again to check it further (better not stir up the neighbors). Looking back, my problems started when I was mowing our property last weekend and I idled the tractor to get a drink and a friend stopped by. I did not shut it down thinking I would be right back but we ended up talking 30 or 40 minutes. After resuming mowing I noticed the coolant smell. Good luck on the house, I hope to be right behind you.

All, my overflow down tube does not bubble at higher rpm even when mowing at 215°F which is the highest temp I have ever ran at (thanks to the board in front of radiator). Do you think this means I am getting low circulation at low rpm (weak water pump) and starting to boil in isolated hot spots of the head? When it cools down I will open the radiator and run it with the cap off to see what circulation I have, should I see much coolant movement across the top of the radiator?

I will also get a diesel rated coolant or use the SCA additive like svcguy recommends to avoid cavitation damage.

Thanks again for everyone’s input, this is a great forum, will keep you posted, Gary

 

[Box]

This might be a too simple to mention but I have to. Are you sure the radiator is not too full? IE filling the radiator to the top and then having a resivoir with fluid in it could make the overflow bottle overflow until proper amount of fluid is in system??

Also, contaminated water could be a cause. If any contaminate got into the system it could be hard to get out. IE radon for instance will gass at atmospheric pressure out of water. Some other contaminates may gass only after getting hot creating the bubbles and the appearance of air getting into system, when in fact the fluid is just letting the contaminates excape in gas form??? Try distilled water and antifreeze with the proper amount of anti-cavation fluid, it may work.

Also, some people will put pepper into a radiator to stop a leak. Hopefully this is NOT the case here. I personnally consider any stop leak or pepper a contaminate and a system flush may not get all of it out.





Just a thought.

I suspect that keeping the radiator to full was part of the problem I was fighting. I think I had a combonation of a bad head gasket or warped head and then I was over filling the radiator and over flow bottle. I filled it like I would a car, left about it about 1/2" or so from the top of the radiator and then filled the over flow bottle to the full mark when the unit was cold. After reading some posts I tried leaving about 3/4" from full in the radiator and filling the over flow bottle to the low mark. This seems to be working as I used the trator some this weekend dragging a blade and brush hogging and it never went past the 1/2 mark on the guage and never over flowed the bottle. Before I replaced the head gasket and had the head surfaced it would have been spewing coolant from the over flow bottle after about an hour.

This does not explain the bubbles I see in the coolant, but as Gary2 has descrided they are not constant, but happen enough that they keep me worried. I am going to compare his findings to what I am seeing and see how they compare.

Box