[Scott Thomson]

Hi everyone, I have a 2003 with the 2.0 that is over heating but we did nurse it home by running the heater full blast. We recently replaced the water pump and I just replaced the thermostat but when I tested it the temp went to 200° (I am watching it on an OBD2 scanner)and the coolant hose at the thermostat never got hot and feels empty. any help would be much appreciated??

 

[Supercharged98]

It could be a few things, air bubble, stuck thermostat, bad water pump, yes, bad water pump. I hope you used a metal impellar style. I've had new thermostat stick shut and get stuck wide open. And, I hope you used the correct coolant, also.

 

[Scott Thomson]

Thanks for the info, I did use the good water pump, I think its ok because the heater still works, when it broke the heater did not work. I am not sure how to bleed air from the system but I will try in the morning and check the thermostat that I removed also,if its ok chances chances are that the new one is ok.

 

[Supercharged98]

First, turn your heater on high at the hottest setting. Open your exspansion tank and top off with coolant to the high mark. Start the engine, and idle until thermostat opens and circulates the coolant. If there is any trapped air it will heat up faster than the coolant and it will burp out the tank. Shut off the engine, wait a minute until the coolant descends back into the engine. Top off the expansion tank and do it again. It took my car 4 times to get all the air out. Once it stops burping, shut down and check level of coolant and replace cap.
Make sure you don't use green coolant or the blue universal kind. It doesn't work in VW's.

 

[Scott Thomson]

Right I have the car running in the driveway its 65° and the scanner is showing the temp at 200° and the coolant is not flowing. I hit the block at the thermostat housing with with a laser temp gage and shows 175-180°. what up with the green coolant??

 

[PRM502STREET]

It's possible You have an air pocket in the cooling system

Sent from my ZTE-Z990G using AutoGuide.Com Free App

 

[PRM502STREET]

Oops sorry Wasn't paying attention Welcome to the org

Sent from my ZTE-Z990G using AutoGuide.Com Free App

 

[Supercharged98]

It doesn't agree with our aluminum engine component cars. I hope and pray you didn't mix the green with the pink G12 coolant.

 

[IndyTom]

It doesn't agree with our aluminum engine component cars. I hope and pray you didn't mix the green with the pink G12 coolant.

I agree you should never mix coolants. The mixture of two incompatible coolants can turn into a muddy brown and could cause issues if not corrected.
That said it should not cause overheating as you are describing. If the waterpump is operating properly then the fault must be your thermostat. One thing I learned the hard way was never save pennies on the Thermostat. Only buy the Original VW type thermostat. I once bought a cheap Whaler brand Thermostat for my Audi TT and that was a disaster.
Anyway, I would swap out the Thermostat with the proper VW brand T-Stat and I bet things will improve.

Volkswagen New Beetle 2.0 > Search > Thermostat > ES#261231 87C Thermostat - 050121113C

Also if you haven't already swap out your Coolant Temperature sensor especially if you still have the original "Black top" sensor. Replace it with the new "Green Top" sensor ASAP. If those things go they can cause all sorts of problems.

Volkswagen New Beetle 2.0 > Search > Temperature Sensor > ES#264174 Coolant Temperature Sensor With O-Ring & Clip - 4 Pin - 078919501CKT

Since you have a 2.0 and a 1999 Beetle. Make sure you choose the proper Coolant sensor. Some 1998 and 1999's still came with the Blue Square top connectors. Later they all switched to the Black/Green Square/Round connectors.

There is some coolant you can buy. 2 bottle's should be plenty.
http://www.ecstuning.com/Volkswagen-New_Beetle--2.0/Search/Coolant/ES259379/


Good Luck and keep us posted!

 

[Scott Thomson]

Thanks for the welcome and all of your input. I don't know when the coolant was changed but its been green for years and I cant remember it ever being red, I did get the car with 20K miles on it.

Sense my last post when I left the engine running the thermostat did finely open but the temp on the scanner went to 210-213°, while running at this temp the Fans did not come on, does anyone know when the fans are supposed to start?

At this point I am assuming that the water pump is working because the heater is working and the water flowed when the thermostat finely opened.
I also believe that the coolant temp sensors are good because I am seeing both temp levels on the scanner

So now I have moved on to the Fans
I checked the fans from the connector attached to the Cooling fan thermo switch in the lower driver side of the radiator as described in my Haynes repair manual, I found that the low speed side did not work and the high speed side did. When I did the check I could here the Fan Control Module click in for the high speed but nothing for the low speed.
I think it may be time to get a new Fan Control Module.
Does anyone know what the sequence for the fans are? are the fans supposed to run when the AC is on?

 

[IndyTom]

Thanks for the welcome and all of your input. I don't know when the coolant was changed but its been green for years and I cant remember it ever being red, I did get the car with 20K miles on it.

Sense my last post when I left the engine running the thermostat did finely open but the temp on the scanner went to 210-213°, while running at this temp the Fans did not come on, does anyone know when the fans are supposed to start?

At this point I am assuming that the water pump is working because the heater is working and the water flowed when the thermostat finely opened.
I also believe that the coolant temp sensors are good because I am seeing both temp levels on the scanner

So now I have moved on to the Fans
I checked the fans from the connector attached to the Cooling fan thermo switch in the lower driver side of the radiator as described in my Haynes repair manual, I found that the low speed side did not work and the high speed side did. When I did the check I could here the Fan Control Module click in for the high speed but nothing for the low speed.
I think it may be time to get a new Fan Control Module.
Does anyone know what the sequence for the fans are? are the fans supposed to run when the AC is on?

Some may argue this but as long as "ALL" of your coolant is one type that is compatible with aluminium parts (which all of them are these days) then you should be okay. Glad your T-Stat finally opened up. I still say swap it out for a VW Brand T-Stat. It seems this one opens a bit late. The stock unit is a 87degree celcius Thermostat which is about 188.6 degrees Fahrenheit. It should open no later than 200 -204 degrees Fahrenheit. Anything higher and I would be worried.
Yes, the Fans should kick in with the AC on. If they don't than you do have some electrical Gremlins. Anything from a switch to the Fan Control Module to the Fans themselves. I had a bad Thermal switch and my fans were stuck on HIGH at all times. It took me a while to trace the problem but a new switch did the trick. So far no more issues. I actually have a set of fans and a fan control module that I never installed since the switch fixed the issue. Let me know if you would be interested in either and I make you a good deal.
Good Luck and Keep us Posted!.

 

[IndyTom]

I did some more research on why to use G12 VW coolant in our engines and it's not because of the other coolant not being compliant with an alluminum engine but because the store bought type (Green or otherwise) contains ethylene glycol which is like a slow acid for our cars eating away at internal parts, sensors and hoses. So it would be advisable to only use VW recommended G12 fluid in our engines.

Vw Coolant - Vw G11 G12 Coolant - Pink Purple Vw Coolant

 

[Scott Thomson]

Thanks Tom,
I had already swapped out the the T-Stat and when the coolant didn't seem to flow I checked the one I pulled out and it opened at around 180-190° witch sounds good. I am going to replace the fan control module because I couldn't get to run the fans at slow speed. I will follow up later with how it goes.
Thank you all again.

 

[Scott Thomson]

Hi all,
Found out I was testing the fans incorrectly, Both hot wires need to be connected to run hi speed, one for low and the second for high. Either way I have replaced the thermostat, fan control relay and the fan control thermo switch. I wormed up the car untel the thermostat upend and ran it around the block, I then check the thermostat housing with the laser temp gage and it was about 203° (my kid took of with the scanner so I could not get a system temp)and still no fans, I then turned on the AC and the fans would run intermitently. I am pretty sure that the fans should run continusly when the AC is on, is that right?
any sugjustions would be apriciated.

 

[esse10]

sludge

Going by what you said about using the green coolant It could be that part of your radiator is klugged with brown sludge. Also if your engine block is running hotter than the radiator because of poor circulation through the radiator the A/C system will shot down and you cannnot turn on the fans via pushing the A/c switch and the fans don't turn on becuase the radiator thermal switch is not hot enough. So I think it's your radiator plugged up or partially plugged up. Good luck man

 

[Scott Thomson]

At this point the fans only run intermittently when the engine is very hot I am going to check the radiator but why don't the fans run all of the time when hot?

 

[D2Beetle]

Perhaps one of the Threads below would be helpful ...

1) ... Lower Radiator Sensor
2) ... Fan Test

 

[Scott Thomson]

I ran a test today with the scanner hooked up, I started the car cold and for the most part just let it idle and worm up. I keep my infered gun on the hoses to see when the thermostat opened up while watching the engine temp on the scanner, the thermostat opened when the scanner was showing 199-200°, when the thermostat opened the temp held for a couple of min. but continued to rise after that. I shut off the engine when the temp hit 215° and the fans never started.
When the thermostat opened up the temp of the hoses equaled out right away (i am having a hard time believing that the radiator is clogged) I turned the AC on when the temp was at 200° and the fans still run intermittently, 3sec. on 10sec off. The other night I let the temp go to around 218° and the fans did the same thing without the AC on.

 

[bme]

Either way I have replaced the thermostat, fan control relay and the fan control thermo switch.

Do you mean fan control module or a relay? Fan control module (I think) should be in the engine compartment as opposed to the relay panel. If you have not I would take IndyTom up on his offer. I had this problem on my cabrio and replaced the FCM, but still had the same problem. I new it had to be a bad new part but wasted a week checking everything and had no air conditioning in the AZ summer, replaced it and was all good. The FCM's effect all kinds of things.


Sent from my iPad using Autoguide

 

[Scott Thomson]

I have replaced the Fan Control Module, Fan Control Thermo Switch, Thermostate and the Temp Sensor. I am going to start testing all the fan control wiring to see if I have any broken wires or conections.

I beleive thet when the AC is running that the right fan should come on and run continuously, can anyone conferm this?

Thanks everyone for all your help