GOLFMK8
GOLFMK7
GOLFMK6
GOLFMKV

Car over heating

A

Allchokedup

Autocross Champion
Eviscor said:
Is the metal waterpump you installed the aluminum one made by Graf that comes with a thermostat and coolant temp sensor?

If so, your problem is more than likely the thermostat. Its a cheap motorad brand.

I installed the Graf waterpump last weekend and had similar symptoms as you and found some coolant on lower radiator hose going into the waterpump. I thought I still had air in the system even though I vacuum filled with coolant and idled afterwards until radiator fans kicked on.

Decide to pull waterpump, remove thermostat and put the oem and motorad thermostat in boiling water, needless to say motorad barely opened.

I did log the temp with vcds and had coolant temperature as high as 113C with the motorad thermostat (comes with the graf waterpump). After I installed the waterpump again with oem thermostat, vcds logged temp no higher than 105C and 90% of the time at 98-101C. This is with the temp. outside at 88F in high humidity.

I hope this helps and for anyone that buys a graf waterpump, make sure you put the oem thermostat in.
Click to expand...

Not sure of the what manufacturer the pump is but it is the alum one. I bought from ECS, I put a new swirl tank on yesterday and need to run the car some today to see if its fixed. I did notice a bit of water outside the tank and what looked like it may have been a hole.
If I have to pull the thermostat I'm going to be pissed! But will be glad it's fixed. It's the strangest thing and sometimes it will get a tad above 190 and stay there. Which makes the thermo very suspect. Will let you guys know, hopefully wife will alot me the time to work on it. Lol
She is ready for me to buy a new car...psshhhhhjj...
 
A

Allchokedup

Autocross Champion
zrickety said:
Try this and make sure there is no air in there. I run the car cold to hot with the radiator cap off, squeeze hoses, top off, monitor temps from the obd2 port. You might have trapped some air by bypassing the heater core, it's hard to say. You can hear the electric pump running when the car is off...
Click to expand...

I have went through these procedures at least 50 times! Even parked on the curb so the tank would be at highest point so air could make it's way out. So we will see today..
 
E

Eviscor

New member
Allchokedup said:
Not sure of the what manufacturer the pump is but it is the alum one. I bought from ECS, I put a new swirl tank on yesterday and need to run the car some today to see if its fixed. I did notice a bit of water outside the tank and what looked like it may have been a hole.
If I have to pull the thermostat I'm going to be pissed! But will be glad it's fixed. It's the strangest thing and sometimes it will get a tad above 190 and stay there. Which makes the thermo very suspect. Will let you guys know, hopefully wife will alot me the time to work on it. Lol
She is ready for me to buy a new car...psshhhhhjj...
Click to expand...


Its probably the one made by graf as the only other aluminum waterpump I know of is uspmotorsports one.

It certainly is the strangest thing, mine would be at 190F too, but then the coolant temp needle would suddenly start increasing as I put more load on the engine (going uphill). It made me think that the waterpump impeller design was inferior to oem and could not flow enough.

What really made me suspect the thermostat was when I felt the lower radiator hose it was still cold after a long run (normally should be lukewarm if thermostat opened). Also, vcds show radiator coolant outlet temp at 35C, should have been much higher if thermostat was fully opened (when parked idling after long run).

Overall though, the Graf aluminum waterpump is a nice piece with an oem-like impeller design, just has a cheap thermostat in it.
 
Last edited:
A

Allchokedup

Autocross Champion
Drove for 20 min came home parked in driveway and it went a tad over 190. Coolant is full and the only other thing it could be is the pump(hopefully just thermostat). Will update later...
 
A

Allchokedup

Autocross Champion
Did a thermostat delete:)
Its pretty upsetting it's a brand new stat and its wonky. No question about it. Went for a 30 minute drive in 95d didnt move past 190. I wonder if ecs will compensate me for my time? Thanks for all those that had feedback!
 
A

Allchokedup

Autocross Champion
Well..you cant successfully run your car without the heater core attached. Got it hooked back up and no issues at all. I assume it has to do with the little hose that comes off the core. So, dont bypass the heater core, you will have symptoms of air pockets and a sticky thermo..illogical I know but its vw

Edit, I installed a new thermo and it would over heat randomly, this led me to putting all back (thx stockgti) and working from there
 
zrickety

zrickety

The Fixer
Eviscor said:
I hope this helps and for anyone that buys a graf waterpump, make sure you put the oem thermostat in.
Click to expand...
I had read this thread years ago. Just installed my Graf and it's running hot. Did the radiator too. I'm assuming the cheap thermostat, going to change it out.
 
V

VgRt6

Ready to race!
I had the same problem with the Graf aluminum water pump. The garbage thermostat only lasted a few thousand miles. Put a VW thermostat in and everything works perfectly. I assumed the coolant temp sensor and O-ring were also garbage and replaced those as well.
 
T

Turbo Beetle

Ready to race!
VgRt6 said:
I had the same problem with the Graf aluminum water pump. The garbage thermostat only lasted a few thousand miles. Put a VW thermostat in and everything works perfectly. I assumed the coolant temp sensor and O-ring were also garbage and replaced those as well.
Click to expand...
Were you able to make the replacement of the temp sensor and thermostat without removing the water pump?
 
V

VgRt6

Ready to race!
Turbo Beetle said:
Were you able to make the replacement of the temp sensor and thermostat without removing the water pump?
Click to expand...
I decided to de-carbon the intake valves at the same time, so I removed the intake manifold and then the water pump. The valves needed to be cleaned, and it made it a lot easier to replace the thermostat.

I watched a video on YouTube where someone replaced the thermostat without removing the pump, but they did have to loosen the pump bolts and pull the pump away from the block a little to get access to one of the two thermostat cover bolts. The extra room also helped get the old thermostat out and the new one in, which is tight if the pump isn’t loose. I was paranoid about having a leak from the water pump gasket if I did it this way, and that along with the valves needing to be cleaned made it an easy decision to pull the pump.

Replacing the temp sensor without pulling the pump is easy, but you have to remove, or at least move out of the way, a bunch of the things that you remove to pull the intake manifold. This also played into my decision.
 
T

Turbo Beetle

Ready to race!
VgRt6 said:
I decided to de-carbon the intake valves at the same time, so I removed the intake manifold and then the water pump. The valves needed to be cleaned, and it made it a lot easier to replace the thermostat.

I watched a video on YouTube where someone replaced the thermostat without removing the pump, but they did have to loosen the pump bolts and pull the pump away from the block a little to get access to one of the two thermostat cover bolts. The extra room also helped get the old thermostat out and the new one in, which is tight if the pump isn’t loose. I was paranoid about having a leak from the water pump gasket if I did it this way, and that along with the valves needing to be cleaned made it an easy decision to pull the pump.

Replacing the temp sensor without pulling the pump is easy, but you have to remove, or at least move out of the way, a bunch of the things that you remove to pull the intake manifold. This also played into my decision.
Click to expand...
Thanks for your response. I have seen the video you mentioned and was hoping there might be a better option than in the video. I replaced my pump plastic pump with the Graf pump and found out the sensor and thermostat in the Graf pump were bad. I replaced the sensor and thermostat by removing the Graf pump and the sensor is now good but the replaced thermostat doesn't open until 210 -215°F. My car is a 2012 Turbo Beetle so the multi function display always switches to display 195° as soon as it hits 195° and stays on temperature until I scroll other options to reset. I have checked for air bubbles in the coolant systems and also verified several time with a laser temperature gauge that the car temperatures sensor is accurate.
 
V

VgRt6

Ready to race!
What brand thermostat is installed now. For stuff like that where it has to work right and is a pain to replace I always use VW parts. I should have installed one in the Graf pump proactively, but didn’t think about.
How have you determined that the thermostat isn’t opening until 215-ish degrees?
 
T

Turbo Beetle

Ready to race!
VgRt6 said:
What brand thermostat is installed now. For stuff like that where it has to work right and is a pain to replace I always use VW parts. I should have installed one in the Graf pump proactively, but didn’t think about.
How have you determined that the thermostat isn’t opening until 215-ish degrees?
Click to expand...
I think the last thermostat is a Rein. When the MFD reads 210-215°F the lower radiator hose will start to heat up but before that the lower radiator hose does not get above 80-90°F at most. When the multi function display reads 210-215°F I verify temps with a laser temp tool using it under the hood at the over flow tank and at the top radiator hose which will read 200 to 210°F when the MFD is at 210-215°.
 
You must log in or register to reply here.
Top