I've been thru this a hundred times at least. Back in the 70/80s any car or truck that had a Heavy Duty Cooling/Tow Package came with more rows in the radiator, a different water pump than standard. The HD Cooling system always had fewer blades on the water pumps impeller. 5 vs 7 to slow the coolant down as these systems also came with lower gear ratios. The reason being that the coolant becomes aerated(cavitation) from the higher revs/added blades.
I've known people who actually caused their old school vehicles to overheat from pulling the thermostat because the water pump cavitated so much that it was basically trying to push air bubbles and foam through the cooling system. Plus, an engine that never properly warms up uses more fuel and the oiling of the top end suffers because thick oil is harder to pump and slower to drain back to the pan.
It does run colder without the thermostat but the reason the thermostat opens when it does is to do with thermal efficiency the thermostat is there to make sure your engine stays in a temperature range where the engine would be most efficient
I used to have your logic, but experience has shown me there is more to it than just moving coolant. 1. The coolant needs to stay in the radiator long enough to be able to exchange the heat. I have toyed around with various size restrictors till I found the happy balance. Problems usually show themselves under specific conditions. 2. When cold the thermostat creates a vacuum allowing the system to recover the coolant that was expanded in to the tank. 3. Not all cooling systems work the same way. European cars will overheat without one. They have a dual stage set up. In the end I realized this only works in some situations in others it creates problems. Usually its just best to remove the spring and put the assembly back cuz that's about the right flow for the max cooling. 30 years of living with broken sht. Edit. The manifold should be a certain temp for proper fuel atomization.
Interesting video as I watch and read viewer comments pos and neg at least you shared real world experience and I appreciate that as many of people have trashed a engine or blew a head gasket over heating them due to a sticking thermostat. Under a few situations we have drilled a 1/8 or 3/16" hole to insure some flow at all times not overly effecting warm up times.Again Thanks
I drive a jeep with a gutted thermostat. It's a manual. Have seen it get hot coming off freeway to a red light. But just rev the engine and temp drops. On trails it happens more often. Lot of gas to get over something then sit and wait. Also seen this with hot laps at dragway on other vehicles. They make water restrictors to go in place of a thermostat for a reason. Yes an engine needs to get to proper temp. Which temps are different for iron engines and aluminum.
You’re missing what happens to the dynamic pressures in the block. We did plenty of tests back in the day with pressure gauges all over the block and heads. As the engine revs up, the dynamic pressure increases which increases the actual boiling temperature and also helps prevent cavitation.
@@Alaska_Engineer yes, there are many factors I’m skipping in favor of brevity in this case. This demonstration was solely to show the relationship between flow rate and heat transfer, because at the base level there are a lot of people who incorrectly think that coolant with a higher ‘dwell’ time in the block will pick up more heat. I figured the simpler the demonstration the easier it would be to grasp quickly.
Old School Mechanics . If it Overheats FIRST Look Under your Oil Cap . Second remove the Thermostat , until you can do a Cooling system flush . The Thermostat is there to , as its name implies , keep the Temps Steady . Excess heating and cooling in operation WILL make the Head Gasket fail prematurely .
As a 3rd generation mechanic and engine builder you do understand that once the thermostat is open it has no bearing on the engine temperature. Using different temperature ranges will not change your operating engine temperature. Only how quickly they open. Once open they have zero influence on operating temperature.They are used so you will have heat in the winter.
@@owenhill-vf7ko . Analyse the Name . Thermo - and - Stat(ic) . If the desired , Pressurized Running Temp is , say 90C , then you get a Thermostat that opens at 87 Temp . If the Cooling system is Healthy and correctly Engineered , it should in fact be able to OVER-cool the Engine . This means that when the Coolant Temperature drops to , say 85 , the Thermostat will close off a bit to " Throttle " the Coolant and thus MAINTAIN the desired 90 . THAT is what a Thermostat does , having a Heater circuit has F/A to do with it . That is a separate valve and piping system . It's so important that lots of Big Truck Diesels have a Computer Controlled Cooling System to keep the Engine within 2 degrees of the desired Temp . Thermal Expansion/Contraction and stuff..................
I would never remove the thermostat on a modern computer controlled engine unless I had a stuck thermostat that caused overheating and I was in a bind to get my vehicle running. Old school engines are not as fussy about operating temp.
Engines are designed to run at a certain steady temperature, not as cool as possible, plus head gaskets and seals can prematurely fail over time by not warming up and running at a specified rate/temperature.
If going to a larger radiator I gut the thermostat. Not remove it. If you ever do hot laps at drag way or 4x4 on trails they make a disc with different sized holes in it. Velocity matters and without restriction you can get slower velocities. Like a hose vs a hose with a nozzle.
Engines are designed you know the bearings rings etc to work and live longest at a desired temp removing the thermostat lowers that considerably in most cases not only that in today's cars the computer uses sensors for everything one of them is the temp sensor if it never gets up to temp then the computer thinks it's a cold start constantly which in turn never goes into what's called closed loop and the air fuel mixture in not closed loop because it thinks it's in a cold start constantly is super one sided way more fuel than air. Thus using more fuel could be a lot more fuel even in some cases in fact any time you have a check engine light on your fuel mileage is suffering closed loop is where the computer is taking all the inputs from all the sensors and supplying the engine with the least amount of fuel possible at any given time and keep the engine alive too lean conditions are detrimental more. So usually than a rich condition rich too much fuel lean too much air
I have a 1990 firebird if you remove the thermostat it will not go into overdrive I know that because when I replace the engine the one I put in there had a stuck open thermostat and the engine will not come up to proper temp for the computer do let it shift into overdrive because it was still trying to heat the engine to proper temperature
I've been thru this a hundred times at least. Back in the 70/80s any car or truck that had a Heavy Duty Cooling/Tow Package came with more rows in the radiator, a different water pump than standard. The HD Cooling system always had fewer blades on the water pumps impeller. 5 vs 7 to slow the coolant down as these systems also came with lower gear ratios. The reason being that the coolant becomes aerated(cavitation) from the higher revs/added blades.
I've known people who actually caused their old school vehicles to overheat from pulling the thermostat because the water pump cavitated so much that it was basically trying to push air bubbles and foam through the cooling system. Plus, an engine that never properly warms up uses more fuel and the oiling of the top end suffers because thick oil is harder to pump and slower to drain back to the pan.
It does run colder without the thermostat but the reason the thermostat opens when it does is to do with thermal efficiency the thermostat is there to make sure your engine stays in a temperature range where the engine would be most efficient
I remove the thermostat from my vehicle every spring and put it back in late autumn. I have had this vehicle 28 years and counting.
I used to have your logic, but experience has shown me there is more to it than just moving coolant.
1. The coolant needs to stay in the radiator long enough to be able to exchange the heat. I have toyed around with various size restrictors till I found the happy balance. Problems usually show themselves under specific conditions.
2. When cold the thermostat creates a vacuum allowing the system to recover the coolant that was expanded in to the tank.
3. Not all cooling systems work the same way. European cars will overheat without one. They have a dual stage set up.
In the end I realized this only works in some situations in others it creates problems. Usually its just best to remove the spring and put the assembly back cuz that's about the right flow for the max cooling. 30 years of living with broken sht.
Edit. The manifold should be a certain temp for proper fuel atomization.
Thermostats are helpful in cold climate areas as they help the engine warm up faster
Thank you so much , I agree , went 12 year on my 1973 Datsun 610 , always ran cooler
Interesting video as I watch and read viewer comments pos and neg at least you shared real world experience and I appreciate that as many of people have trashed a engine or blew a head gasket over heating them due to a sticking thermostat. Under a few situations we have drilled a 1/8 or 3/16" hole to insure some flow at all times not overly effecting warm up times.Again Thanks
I drive a jeep with a gutted thermostat. It's a manual. Have seen it get hot coming off freeway to a red light. But just rev the engine and temp drops. On trails it happens more often. Lot of gas to get over something then sit and wait. Also seen this with hot laps at dragway on other vehicles. They make water restrictors to go in place of a thermostat for a reason. Yes an engine needs to get to proper temp. Which temps are different for iron engines and aluminum.
You’re missing what happens to the dynamic pressures in the block.
We did plenty of tests back in the day with pressure gauges all over the block and heads.
As the engine revs up, the dynamic pressure increases which increases the actual boiling temperature and also helps prevent cavitation.
@@Alaska_Engineer yes, there are many factors I’m skipping in favor of brevity in this case. This demonstration was solely to show the relationship between flow rate and heat transfer, because at the base level there are a lot of people who incorrectly think that coolant with a higher ‘dwell’ time in the block will pick up more heat. I figured the simpler the demonstration the easier it would be to grasp quickly.
Old School Mechanics . If it Overheats FIRST Look Under your Oil Cap . Second remove the Thermostat , until you can do a Cooling system flush . The Thermostat is there to , as its name implies , keep the Temps Steady . Excess heating and cooling in operation WILL make the Head Gasket fail prematurely .
As a 3rd generation mechanic and engine builder you do understand that once the thermostat is open it has no bearing on the engine temperature. Using different temperature ranges will not change your operating engine temperature. Only how quickly they open. Once open they have zero influence on operating temperature.They are used so you will have heat in the winter.
@@owenhill-vf7ko . Analyse the Name .
Thermo - and - Stat(ic) .
If the desired , Pressurized Running Temp is , say 90C , then you get a Thermostat that opens at 87 Temp . If the Cooling system is Healthy and correctly Engineered , it should in fact be able to OVER-cool the Engine .
This means that when the Coolant Temperature drops to , say 85 , the Thermostat will close off a bit to " Throttle " the Coolant and thus MAINTAIN the desired 90 .
THAT is what a Thermostat does , having a Heater circuit has F/A to do with it .
That is a separate valve and piping system .
It's so important that lots of Big Truck Diesels have a Computer Controlled Cooling System to keep the Engine within 2 degrees of the desired Temp .
Thermal Expansion/Contraction and stuff..................
@@owenhill-vf7ko Thermostats are restrictive compared to an open hole, so they do determine the coolest temperature an engine will run at.
I would never remove the thermostat on a modern computer controlled engine unless I had a stuck thermostat that caused overheating and I was in a bind to get my vehicle running. Old school engines are not as fussy about operating temp.
Engines are designed to run at a certain steady temperature, not as cool as possible, plus head gaskets and seals can prematurely fail over time by not warming up and running at a specified rate/temperature.
If going to a larger radiator I gut the thermostat. Not remove it. If you ever do hot laps at drag way or 4x4 on trails they make a disc with different sized holes in it. Velocity matters and without restriction you can get slower velocities. Like a hose vs a hose with a nozzle.
Engines are designed you know the bearings rings etc to work and live longest at a desired temp removing the thermostat lowers that considerably in most cases not only that in today's cars the computer uses sensors for everything one of them is the temp sensor if it never gets up to temp then the computer thinks it's a cold start constantly which in turn never goes into what's called closed loop and the air fuel mixture in not closed loop because it thinks it's in a cold start constantly is super one sided way more fuel than air. Thus using more fuel could be a lot more fuel even in some cases in fact any time you have a check engine light on your fuel mileage is suffering closed loop is where the computer is taking all the inputs from all the sensors and supplying the engine with the least amount of fuel possible at any given time and keep the engine alive too lean conditions are detrimental more. So usually than a rich condition rich too much fuel lean too much air
The engine and all under hood components will live you, on the other hand the computer likely won't be happy and fuel economy will suffer.
I have a 1990 firebird if you remove the thermostat it will not go into overdrive
I know that because when I replace the engine the one I put in there had a stuck open thermostat and the engine will not come up to proper temp for the computer do let it shift into overdrive because it was still trying to heat the engine to proper temperature
This is not worth watching.