RTV 1100 Overheating

bobie93

New member
Apr 10, 2024
3
0
1
New York
I have an older used RTV 1100 that was bought off of a college. the machine is well used but runs great except it overheats. When it gets how coolant is boiling out of the overflow tank the hose going into the radiator is hot and the hose coming out is cool. the radiator fan is on. Any thought or suggestions on what to check? Water pump seems to be circulating fine.
 

jaxs

Active member

Equipment
B1750HST
Jun 22, 2023
444
218
43
Texas
I have an older used RTV 1100 that was bought off of a college. the machine is well used but runs great except it overheats. When it gets how coolant is boiling out of the overflow tank the hose going into the radiator is hot and the hose coming out is cool. the radiator fan is on. Any thought or suggestions on what to check? Water pump seems to be circulating fine.
I was about to say thermostat isn't working but if that statement is accurate what makes you believe water pump is circulating fine?
 

bobie93

New member
Apr 10, 2024
3
0
1
New York
I was about to say thermostat isn't working but if that statement is accurate what makes you believe water pump is circulating fine?
My assumption that water pump is working fine is that as machine is running if I remove upper coolant cap I see coolant flowing thru. is there a way to test or check that there is proper flow. when machine is running and warming up both hoses are warm but once radiator fan turns on lower one cools of. So could it be a bad water pump. I did have water pump off and it appeared ok and all coolant paths seemed clear. There is a small leak on the radiator but not a lot just enough to make a small drip. Could that cause the issue
 
Last edited:

Vince1230

Active member

Equipment
Bx2370
May 13, 2022
130
49
28
Honey Grove,Pa
Bottom is cool. Could there be a clog. If top hotter than bottom the radiator is cooling. Unless the bottom is cool due to no flow. Is there major difference in temperature.
 

jaxs

Active member

Equipment
B1750HST
Jun 22, 2023
444
218
43
Texas
My assumption that water pump is working fine is that as machine is running if I remove upper coolant cap I see coolant flowing thru. is there a way to test or check that there is proper flow. when machine is running and warming up both hoses are warm but once radiator fan turns on lower one cools of. So could it be a bad water pump. I did have water pump off and it appeared ok and all coolant paths seemed clear. There is a small leak on the radiator but not a lot just enough to make a small drip. Could that cause the issue
Hot upper and cold lower radiator hoses are indictive of NO CIRCULATION or COMBUSTION LEAKING into coolant if coolant is boiling over through reserve tank. Water circulating rules out pump failure and thermostat problem leaving you with possible cracked head,blown head gasket or such. Some people look for bubbles in coolant to check for combustion leak, I prefer using chemical tests. Ask any auto parts house for chemical to test for blown head gasket and cracked head.
 

bobie93

New member
Apr 10, 2024
3
0
1
New York
Hot upper and cold lower radiator hoses are indictive of NO CIRCULATION or COMBUSTION LEAKING into coolant if coolant is boiling over through reserve tank. Water circulating rules out pump failure and thermostat problem leaving you with possible cracked head,blown head gasket or such. Some people look for bubbles in coolant to check for combustion leak, I prefer using chemical tests. Ask any auto parts house for chemical to test for blown head gasket and cracked head.
I will look into this test. I do not see any obvious bubbles but this seems like the route to test. Thank You
 

lugbolt

Well-known member

Equipment
ZG127S-54
Oct 15, 2015
4,880
1,613
113
Mid, South, USA
with a cold engine, pull the fill cap off. Start the engine with the cap off. If it bubbles, you have a blowed head gasket or/and a cracked head.

all it takes is one or two overheats, which are usually due to plugging the radiator with seeds and mud/etc, to hurt a head gasket and/or head. OR, I've seen a few that have had zero coolant maintenance, and the inside of the block corrodes (rusty) and the rust breaks loose to plug up the head gasket and block passages.
 

Teel6060

New member

Equipment
Kubota RTV 1140 CPX
Apr 11, 2024
2
0
1
Southwest Missouri
I have an older used RTV 1100 that was bought off of a college. the machine is well used but runs great except it overheats. When it gets how coolant is boiling out of the overflow tank the hose going into the radiator is hot and the hose coming out is cool. the radiator fan is on. Any thought or suggestions on what to check? Water pump seems to be circulating fine.
Have you checked your radiator screen? If mine gets too dusty it will clog up and overheat.