I have an L275 (approx. 30 yrs old) with a 3 cyl. diesel. I recently experienced coolant dripping from the overflow whenever I would bush hog. I had the radiator reworked by a radiator shop, replaced the thermostat and installed a new pressure cap. The problem is still there but not as bad. My fear now is a high pressure head gasket leak. Any ideas as to how one would diagnose this without hauling the tractor off to the shop? Thanks. Joe
High Pressure head gasket leak
- Thread starter J662West
- Start date
You can fill the rad to the top and watch for air bubbles coming out with the engine running. (with the rad cap off)
Ed
Ed
Maybe you are just keeping the coolant level to high? Those older tractors don't have coolant recovery containers so they require an air space in the rad to allow for coolant expansion.
Ed
Ed
That is a possibility. I used to work at a service station in the sixties as a kid and the rule then was to top it off. I can't seem to find anything in the Kubota manual that tells me at what level I should stop the antifreeze. I'll try and check this out. Thanks.
My radiator has a short neck that goes down into it, I fill it to the bottom of the neck not to the bottom of the cap. I get a little out of the overflow hose some times when working hard but after the first time it stops and doesn't do it anymore.
I also agree you should see bubbles in your radiator if you have a high pressure head gasket leak and possibly fuel in the radiator. I had a car that had a bad head gasket and it made white foam in the radiator. Had a truck that had a leaking head gasket and it filled the radiator with fuel, checked the water one morning and had antifreeze the next morning had diesel fuel.
I also agree you should see bubbles in your radiator if you have a high pressure head gasket leak and possibly fuel in the radiator. I had a car that had a bad head gasket and it made white foam in the radiator. Had a truck that had a leaking head gasket and it filled the radiator with fuel, checked the water one morning and had antifreeze the next morning had diesel fuel.
Had the exact same problem recently and had a bad water pump. The pump wasn't leaking but was not moveing the water good enough for cooling.
Same eng you have.
Same eng you have.
aquaforce
New member
Equipment
L245DT FEL, JD450 Track loader, 5' scrape blade&mower, 5x10 trailer, Dump truck
Sometimes air bubbles are not so easy to see. In these cases a little tool that NAPA usually carries called a "block tester" is a perfect way to test for hydrocarbons in the coolant system. It is not very costly, around $25-30 and works very well in "sniffing" out failed head gaskets, cracked blocks and heads. This tool can find hydrocarbons without getting the engine heated up by working it hard. If I'm looking at a used machine I check the coolant system very well after getting a cracked head slid in on me. 
I agree with others that the coolant level needs to be down from the top. Some radiators have a neck down inside to indicate proper level but if not half way down, between the cap and the core, is a good start point.
I agree with others that the coolant level needs to be down from the top. Some radiators have a neck down inside to indicate proper level but if not half way down, between the cap and the core, is a good start point.
Joe ... I'm in the same boat with you about the Sixties (60s) radiators. What Ed said is true about space in the top of the tank. According to engineers of that day and time; the core was to be covered with coolant and the top of the tank was to be left for thermal expansion, the cap was designed to relieve at the pressure the seals and gaskets could stand before permanent deformation. Hence, the barbed fitting at the neck of the Cap for directing the coolant to the ground through a rubber hose.
When I finished up at MOTECH in Warren, MI in the sixties the High Performance Mopars were all the rage with the young adults of that era. As a mechanic on call for the dealership, I had to chase the parades for the Convertables with the 383s, 426 HEMIS, 440V-6, etc. for overheating due to lack of ram air during slow idle on 90 +degree days. I didn't really understand thermodynamics then like today but that comes with old age experience. What was happening was during predelivery inspection the Mechanics were " topping of the tank right below the overflow tube" and at 212 degrees plus the cap did it job and everybody ( including the pretty girls riding in the Convertibles ) thought the engine was overheating. We would have this same phenomenon today if not for overflow tanks and advanced sensors with electric driven fans on the radiators.
In your case I would only fill the radiator up to the top of the actual core header, run the engine up to temperature and slowly open the cap ( wear gloves, eye glasses and have a thick shop rag over the Cap ) to the safety notch and slowly remove after several seconds during the reaction of the coolant under heat and pressure. Then look down into the neck to see the circulation and aeration of possible air entainment. If this is observed at a constant flow and pulsation of air escaping, I'd say you have engine compression in the coolant system. End of story... you seen to know what's next. You can also dye the coolant system and see if it winds up on the tip of your dip stick with a black light, you know the rest of the needed fix if this is the case too, good luck to you and thanks for sharing your problem with OTT...
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