Evans coolant heat soak problem and solution
10-28-03, 02:18 PM
#1
Evans coolant heat soak problem and solution
Running Evans for a week now with Fluidyne and new Mazda Thermostat with four 1/8 inches holes on the periphery of the thermostat.
Problem: car runs at 180 with A/C fan on no matter the condition (not boosting past 5 psi yet as I got only 130 miles on a Malloy reman). At shutdown, temperature at filler neck starts rising to 250 F within 15 minutes and then drops down to below 180 after 2 hours in 68 F weather. I saw this problem with standard coolant but not as high as 250 (more like 240).
Solution: VW has an electric auxiliary water pump that continues circulating coolant after shut down. The design allows coolant to flow by the mechanical water pump if the electric pump isn't working. Inlet and outlet are 5/8 inch (I think cause I haven't receive the part yet) with an L configuration. This would be perfect for connecting the outlet from the block to the heater hose connection at the firewall driver side. Running this with a 5 minute timer after shutdown.
VW did this to their VR6 only because of the packaging of 6 cylinders into the space of 4 cylinders leading to hotspot after shutdown. This caused cylinder head warpage without an auxiliary electric pump. They have this on the VR6 engine since 1993. Mercedes also do the same on their 190D series.
Anyone done this before?
Problem: car runs at 180 with A/C fan on no matter the condition (not boosting past 5 psi yet as I got only 130 miles on a Malloy reman). At shutdown, temperature at filler neck starts rising to 250 F within 15 minutes and then drops down to below 180 after 2 hours in 68 F weather. I saw this problem with standard coolant but not as high as 250 (more like 240).
Solution: VW has an electric auxiliary water pump that continues circulating coolant after shut down. The design allows coolant to flow by the mechanical water pump if the electric pump isn't working. Inlet and outlet are 5/8 inch (I think cause I haven't receive the part yet) with an L configuration. This would be perfect for connecting the outlet from the block to the heater hose connection at the firewall driver side. Running this with a 5 minute timer after shutdown.
VW did this to their VR6 only because of the packaging of 6 cylinders into the space of 4 cylinders leading to hotspot after shutdown. This caused cylinder head warpage without an auxiliary electric pump. They have this on the VR6 engine since 1993. Mercedes also do the same on their 190D series.
Anyone done this before?
10-28-03, 02:34 PM
#3
oh yeah, it's $110.00 shipped from www.volkswagenpartstore.com
In the VR6 Passat, this electric pump runs at idle and low rpm to assist the mechanical pump and runs in conjunction with a fan after shutoff.
On the VR6 passat, normal coolant temp is 240 F in traffic. I almost jumped out of my friend's car when showed me what the digital gauge was reading. He said it's normal temp due to emission requirement. That's freaking hot for a piston engine!
In the VR6 Passat, this electric pump runs at idle and low rpm to assist the mechanical pump and runs in conjunction with a fan after shutoff.
On the VR6 passat, normal coolant temp is 240 F in traffic. I almost jumped out of my friend's car when showed me what the digital gauge was reading. He said it's normal temp due to emission requirement. That's freaking hot for a piston engine!
10-28-03, 03:01 PM
#4
Senior Member
The only thing I would be leary about is how restrictive the electric pump is when coolant is flowing through it, "like if you installed it into a heater hose to the heater core and the electric pump if off" as most cars have fluid flowing trough them constantly. other than that its a great idea.
10-28-03, 03:07 PM
#5
Lives on the Forum
Re: Evans coolant heat soak problem and solution
Originally posted by pomanferrari
Problem: car runs at 180 with A/C fan on no matter the condition
Problem: car runs at 180 with A/C fan on no matter the condition
10-28-03, 03:30 PM
#6
Originally posted by Tripple 7's
The only thing I would be leary about is how restrictive the electric pump is when coolant is flowing through it, "like if you installed it into a heater hose to the heater core and the electric pump if off" as most cars have fluid flowing trough them constantly. other than that its a great idea.
The only thing I would be leary about is how restrictive the electric pump is when coolant is flowing through it, "like if you installed it into a heater hose to the heater core and the electric pump if off" as most cars have fluid flowing trough them constantly. other than that its a great idea.
Re Damon B statement: 180 F isn't the problem, it's the heat soak that's the problem. Sorry, wasn't clear enough ...
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10-28-03, 04:40 PM
#8
Originally posted by DamonB
Any idea what the current draw and the gallons/hour are on that VW pump?
Any idea what the current draw and the gallons/hour are on that VW pump?
If it's high enough, I might even have it as a supplemental pump during for hot track events. It seems that evans coolant likes high flow rate, it heats up and cool down very quick but doesn't have the thermal mass of water so more flow is better.
10-28-03, 06:32 PM
#11
Lives on the Forum
Originally posted by Brad
uh, where in the hell would you plug it in?
uh, where in the hell would you plug it in?
10-30-03, 10:13 PM
#12
Originally posted by DamonB
Any idea what the current draw and the gallons/hour are on that VW pump?
Any idea what the current draw and the gallons/hour are on that VW pump?
My radiator system has about 3 gallons, that means with a five minute timer, I'll be circulating coolant through the system 10 times.
Once I get it hooked up with a 555 timer into my heater hoses, I'll post some pictures.
10-31-03, 12:20 PM
#13
don't race, don't need to
Just for my edification, which way are you going to drive the coolant? From block, through heater core, into lower radiator connection, through radiator, into filler neck and through block until T-stat closes? Or the other way?
11-10-03, 10:47 AM
#19
Finally got a chance to test my set up which pulls water from the pipe coming out of the block next to the plugs, pumps it up to the heater core and back to the lower radiator hose. Flow rate measured w/o being under pressure is 6 gallons per minute.
Since my fans keep the temp at 185 regardless of outside temp and the temp inside the heated garage is about 60 deg, there shouldn't be any variation from what I saw in the last two weeks (185F rockets to 240F after shut down, back down to 185 after 30-45 minutes).
Note that I'm running Evans NPG+ which has different heat conductive characteristics (0.13 compared to 0.3 for water only and 0.2 for 50/50 mix).
With engine off, temp at 185, I ran the electric pump for 3 minutes. It kept water temp to 210 deg instead of 240. With the fan mod, it shoudn't even get to 210. However, I have the miniature sealed battery so I'm concerned about battery drain with fans and pump running for 10 minutes.
Since my fans keep the temp at 185 regardless of outside temp and the temp inside the heated garage is about 60 deg, there shouldn't be any variation from what I saw in the last two weeks (185F rockets to 240F after shut down, back down to 185 after 30-45 minutes).
Note that I'm running Evans NPG+ which has different heat conductive characteristics (0.13 compared to 0.3 for water only and 0.2 for 50/50 mix).
With engine off, temp at 185, I ran the electric pump for 3 minutes. It kept water temp to 210 deg instead of 240. With the fan mod, it shoudn't even get to 210. However, I have the miniature sealed battery so I'm concerned about battery drain with fans and pump running for 10 minutes.
11-10-03, 11:27 AM
#20
Lives on the Forum
Originally posted by pomanferrari
With engine off, temp at 185, I ran the electric pump for 3 minutes. It kept water temp to 210 deg instead of 240.
With engine off, temp at 185, I ran the electric pump for 3 minutes. It kept water temp to 210 deg instead of 240.
11-10-03, 12:13 PM
#21
built my own engine
a better point to hook it up to, would be the rear throttle body coolant return and the supply coming off the water pump housing
rob @ pineapple said that would work
rob @ pineapple said that would work
11-10-03, 01:56 PM
#22
Lives on the Forum
Originally posted by 93BlackFD
a better point to hook it up to, would be the rear throttle body coolant return and the supply coming off the water pump housing
a better point to hook it up to, would be the rear throttle body coolant return and the supply coming off the water pump housing
11-10-03, 03:40 PM
#23
I'm not clear on the supply side to the water pump? You mean the lower radiator hose with the small nipple for the heater hose next to it?
As for TB return line, well I bypassed the throttle body completely. The coolant comes from the top of the block near the ACV and now runs straight to the small pipes of the rat's nest (which goes to the Turbos).
The reason I picked this particular spot was b/c it was suited to the configuration of the pump with the 90 deg inlet and outlet. I just wanted hot coolant pump out of the block so that it forces coolant (some of it at least) thru the radiator.
To really force coolant thru the radiator, I would need to pump it out of the block from the pipe next the plugs and straight into the TB return line. But the rub here is that the pipe is a 5/8 in and the TB return is a 3/8. Plus there would be lines running everywhere including a T so that coolant could still flow through the heater core.
My configuration at least forces coolant thru the heater core and pulls some of the coolant from the lower rad hose thru the block.
As far as I'm aware, I think I'm the first to do this to an FD so if anyone tries something different with different results, please let me know. I waited for 2 years for somebody to do this but finally got tired of waiting.
As for TB return line, well I bypassed the throttle body completely. The coolant comes from the top of the block near the ACV and now runs straight to the small pipes of the rat's nest (which goes to the Turbos).
The reason I picked this particular spot was b/c it was suited to the configuration of the pump with the 90 deg inlet and outlet. I just wanted hot coolant pump out of the block so that it forces coolant (some of it at least) thru the radiator.
To really force coolant thru the radiator, I would need to pump it out of the block from the pipe next the plugs and straight into the TB return line. But the rub here is that the pipe is a 5/8 in and the TB return is a 3/8. Plus there would be lines running everywhere including a T so that coolant could still flow through the heater core.
My configuration at least forces coolant thru the heater core and pulls some of the coolant from the lower rad hose thru the block.
As far as I'm aware, I think I'm the first to do this to an FD so if anyone tries something different with different results, please let me know. I waited for 2 years for somebody to do this but finally got tired of waiting.
11-10-03, 04:08 PM
#24
Rotary Enthusiast
This is just weird. I have NPG+ and with my fan mods the neck coolant temp never rises over 220 even in 105 summer heat.
The temp rise at the filler neck (radiator inlet) after stopping the car is normal and by running the car in idle for a bit (or turbo timer) will drop the temp somewhat.
If your coolant temp is rising too much, there maybe an underlying problem with you coolant flow path. This could cause uneven cooling, and using the electric pump is simply masking a problem that could get worse.
11-10-03, 04:12 PM
#25
Originally posted by Trexthe3rd
This is just weird. I have NPG+ and with my fan mods the neck coolant temp never rises over 220 even in 105 summer heat.
The temp rise at the filler neck (radiator inlet) after stopping the car is normal and by running the car in idle for a bit (or turbo timer) will drop the temp somewhat.
If your coolant temp is rising too much, there maybe an underlying problem with you coolant flow path. This could cause uneven cooling, and using the electric pump is simply masking a problem that could get worse.
This is just weird. I have NPG+ and with my fan mods the neck coolant temp never rises over 220 even in 105 summer heat.
The temp rise at the filler neck (radiator inlet) after stopping the car is normal and by running the car in idle for a bit (or turbo timer) will drop the temp somewhat.
If your coolant temp is rising too much, there maybe an underlying problem with you coolant flow path. This could cause uneven cooling, and using the electric pump is simply masking a problem that could get worse.
With the fan mod alone, yes I'm seeing the same temp you're seeing.
W/o the fan mod or pump mod, I see 240.
With the pump only, I see 210 and I only have to run the pump for 5 minutes.