I have been trying to help a buddy figure out an over heating issue that is driving me nuts logically with what I know of how thing should work. The car is a 34 Ford with a 350 small block Chevy engine which is stock with internals or cam shaft. The car has a HD Walker radiator and a 15" mechanical fan with a partial shroud to pull through. The car is a relatively new build with every thing new. The car has a 160 thermostat as a starting point. The other day which was 45 degrees outside, we went for a ride up to 8 miles with the temp staying right around 160 degrees, but as soon as we turned on the heater, the temp climbed slowing to 220 with in a half mile. We stopped at a buddies shop for a few minutes to let it cool down. But before we left the car to go in his shop, we checked the upper and lower radiator hoses. The upper hose was hot and the lower hose was cold, which to me indicates a bad thermostat. We visited him about the issue and he agreed with my assumption about the thermostat being the issue and offered up an old thermostat with the innerds removed to try. Back in the car after about 15 minutes it had cooled down and we were on our way back home with out the heater turned on. The temp remained at 160 till we got to a stop lite then it gradually went to 200 degrees while idling there. He had been having it gain in temps during the summer on the highway when using the AC to the point where he would have to stop for a bit so it would cool down on his way to and from the Good-Guys in Des Moines. But the deal with just turning on the heater (Vintage Air water control module) making the engine get hot drives me nuts. Logically the heater should have NOTHING TO DO WITH THE ENGINE TEMP!!! The water control module has the water going thru it the correct way from out of a port on the intake manifold that is on the drivers side of the thermostat housing. To me that is a bit strange as most outlets are on the passenger side. Logically I am thinking that having the outlet straight up from the intake on the drivers side next to the thermostat housing is causing some turbulence making the thermostat close while the heater is turned on and warming the engine up. Once back home we drained the entire engine of coolant and did a vacuum test on the system with 20" of vacuum that it held for 30 minutes with no variance, then took out the original 160 thermostat and installed the gutted out thermostat and reloaded all the coolant. Then we went for another ride, this time for 20 miles with the temp not even getting to 100 degrees even with the heater turned on at all highway speeds indicating to me it was thermostat related. It didn't even warm up over 100 at a stop lite because of sitting with the slow idle . My friend has changed 160 degree thermostats 3 times during the summer because of the over heating going down the highway. I have always felt once a thermostat gets warmed up way past where it is supposed to work it is no good any more. Having it get warmed up at stop lites while idling to me means there is not enough water being pumped by the water pump and the fan isn't large enough to pull adequate amounts of air across the HD radiator. The water pump pulley is the correct size being smaller (6 1/2") than the crank pulley (7 1/4") so that is not the issue. My suggestions to my friend is to get a new high flow 160 thermostat, a new high flow water pump that has more impellers to push more water, a new 6 or 7 bladed 18" fan, and a new shroud that is tight all around the fan that pulls from the whole radiator. I believe tall those items should solve his heat issue. But if it continues to heat up after installing these new parts when the heater is turned on, I will be dumbfounded still thinking it is intake manifold heater outlet placement related!! The gauge read correctly when checked with laser temp reader. Nothing makes sense..... Am I missing something??
Hot Rod
- Thread starter Hot Rod
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63impaloligist
Well Known Member
Normally you would come out of the water pump to the core, then to the passenger side of the intake manifold. Some of the newer cars with reverse rotation water pumps, TBI and TPI, had the water coming from the rear of the intake manifold, to the core, then out to the radiator directly. Therefore the pump had no outlet, but a plug on the top. The temp sensor for the gauge would be on the drivers side in the manifold or cylinder head. Due to it being the hotter side of the engine. 5 and 7 adjacent in the block and standard firing order.
A few years back a friend & myself loaded up our street rods and headed for PUEBLO COLORADO , street rod NAT. He was having similar issues with his 37 ford cpe. I pulled an early 289 Ford Mustang engine , very radical ,low mile out of my 48 & sold it to him. The only prob. I had it was a "ford" . He bought an aluminum WALKER radiator from someone he knew , H e had heating issues bad up in the mountains , my ZZ4 was coool . KOA would not let you work on cars on the property , pulled in my inclosed trailer and good to go. I told him it looked like a 2 core radiator, while at the show a WALKER REP. was on site, he said Walker never made a 2 core, when we got back to MO. he pulled the heads had them checked & re-surfaced, detuned the engine, changed the dual line holly carb. and pressure tested cooling system , to no avail. Went to a friends happy hour one night , his friend builds very high end cars , he looked at Randys engine , first thing he said, you need to pull that 2 core radiator , and see what happens, next stop was a radiator repair shop, the guy at the shop said YUP 2 core. Randy went home , ordered a 3 core alum. no name rad. prob. resolved , he spent about $1500 on the other issues to resolve and no help! He called WALKER and got the same rep. and remembered RANDY from the show , he checked again , he said oh yes they made a 2 core in 2007,8,9 ??? , needless to say the rep. got an ear full. Just Saying --- GOOD LUCK
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I drilled a small hole (1/16") in the 180 degree thermostat in the early 350 SBC in my '33 Ford as a bypass and it works fine. I am running an electric fan that is triggered to turn on at 185 and off at 175. I am not running a heater or A/C in the roadster.
Your comment about it getting hot when you turn on the heater surprises me. I generally think of a car's heater as another radiator that will get rid of heat in the engine's cooling system, not create it.
Your comment about it getting hot when you turn on the heater surprises me. I generally think of a car's heater as another radiator that will get rid of heat in the engine's cooling system, not create it.
Sure sounds like coolant flow issue. Is the coolant flowing too fast through the system when the heater is on? Or is the coolant flow being "diverted" to the heater core and away from the radiator for some reason? Reverse flow water pump?