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Old 02-21-2010, 04:13 PM
ptgRegistered Member ptg is offline
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Default 99 VW Beetle Coolant / Overheating problem

My '99 Beetle is overheating with the red light blinking after 10-15 minutes of driving. Also, no hot air is coming out when the heater is turned on. I've already flushed and refilled the coolant with G12. I've also replaced the A/C switch and Coolant Temperature sensor, but still no go.

When I opened the hood and turned the heat to full blast, I noticed that one of the fans are not running. Also, I can feel that the upper radiator hose is very hot and full of coolant. The lower hose is cool, and also full of coolant, so I don't think there is any air trapped in the system.

What should my next move be? Change the coolant thermostat? Water Pump? Which one first? Any help would be very much appreciated!!
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Old 02-21-2010, 04:21 PM
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How many miles on the car? Have you changed your water pump and timing belt yet? Do you notice any leaks?
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Old 02-21-2010, 04:34 PM
ptgRegistered Member ptg is offline
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Quote:
Originally Posted by Smileybug View Post
How many miles on the car? Have you changed your water pump and timing belt yet? Do you notice any leaks?
105k miles and to the best of my knowledge, neither the timing belt nor the water pump has been changed yet. I did not notice any leaks at all. Everything was working fine until a few days ago...when the red blinking light just came on. I initially flushed the coolant and refilled with regular anti-freeze (not G12), but I flushed and refilled yesterday with G12. Still no go. Overheating and no heat coming out.
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Old 02-21-2010, 04:52 PM
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My vote would be water pump, especially at that mileage. If neither has been done, you are on borrowed time anyway. Get them both changed. The time for the belt is 80k, though its usually done before then, mostly due to the water pump failure.

You can get a kit with the timing belt, water pump, and also a thermostat (which could be a culprit at the mileage too).
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Old 02-25-2010, 08:11 PM
ptgRegistered Member ptg is offline
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My girlfriend bought this car used at 70k, so I'm not sure if the timing belt/water pump was changed before that or not. Is there any way that I can tell?

So, I just changed the thermostat. How can I tell if the old was one was stuck on closed or not? The car is still overheating. The upper radiator hose feels hot to the touch, but the lower radiator hose is cool. I am stumped. I guess it could still be the water pump. Any ideas?? Replace the water pump?
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Old 02-25-2010, 08:36 PM
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I would say if you don't know if its been done, then its probably a good idea to change it out.

Also, is it actually overheating? Or is the light just coming on? A bad coolant temperature sensor could also be a culprit. Cheap and easy to replace.
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Old 02-25-2010, 08:39 PM
ptgRegistered Member ptg is offline
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I've already replaced the coolant temperature sensor. I'd rather not put any more money into this money pit unless I had to... I'm trying to figure out the problem and not just keep replacing random things...
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Old 02-25-2010, 11:43 PM
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Quote:
Originally Posted by ptg View Post
I've already replaced the coolant temperature sensor. I'd rather not put any more money into this money pit unless I had to... I'm trying to figure out the problem and not just keep replacing random things...

I really wouldn't call it a moneypit because it really isn't. You're in the same boat as me, fixing the things the previous owner didn't do. Its really a great car once you get it to where it needs to be. Unfortunately, it just takes a while to get there but it will be worth it in the end.

I was in your shoes about to sell my car amonth ago, but then for one day, it ran perfectly and i had no issues with it and remembered all of the reasons i bought the ar in the first place. Unfortunately, i still stare at every Mazda 3 and Volvo S40 that passes, but i know i'll NEVER own one for the simple fact that its not a Vw, Audi, Porsche, Bently, Seat, ect

Ok, now to the problem. I highly recommend you just take it to a Vw Mechanic (NOT THE DEALERSHIP UNLESS YOU WANT TO PAY FOR OUTRAGEOUS LABOR RATES) near you. Here is a list of trusted local mechanics listed by state. They are TDI shops, but iirc, most of them will work on the gasoline engine ones too. They can inspect your waterpump and timing belt too.

I STRONGLY doubt its ever been replaced and now is the time for you to start saving up for you to get it fixed. I JUST dropped off my car to a local VW performance shop (with a lot of the cool people I've met at the local Wednesday GTG) and the total cost of mine was $427.17 for parts AND labor. Its not too bad if you find the right place.

To sum it up, take it to a shop first and then go from there.

Good luck and hopes this helps.
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Old 02-25-2010, 11:43 PM
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Default Overheating

I've been working through a bunch of overheating issues on my '99 2.0. Had it for a couple of months & am still sorting stuff out.

First question--is it really overheating, or are you getting a spurious flashing light? Ck your owner's manual, but I was under the impression that the coolant level sensor can throw the red flashing ligt--so if the sensor or wiring is bad, that might do it. A Vagcom check will tell you the actual coolant temp.

Does the radiator feel hot top to bottom?

Re: the thermostat, take the old one and put it in a pot of boiling water. Hold it off the bottom of the pot with a wire so you don't fry it. If you have a digital kitchen thermometer, stick the probe in the pot (off the bottom). T-stat should hold water when it's cold, and it will drain through when >87 C if a tstat is good. So even without a thermometer, should open in boiling water as long as you live below about 6500' altitude.

BTW, Prolly not your problem, but I had a heck of a time getting the air out of the heater core and lower radiator when I changed coolant. Lower radiator air was causing the fan switch to stay cold even though the coolant was hot. Finally ended up jacking up the right side of the car, massaging hoses, changing engine speed, and bleeding the lower radiator valve. Strange that there would be air low in the radiator, but there must be a baffle in the side tank to separate the upper and lower chambers.
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Old 02-25-2010, 11:54 PM
ptgRegistered Member ptg is offline
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I really appreciate the list of vw mechanics. I've already spent about a week and a half mucking around with the car with no resolution, so I'm pretty close to throwing in the towel and bringing the car to the mechanic.

I only say that it's a moneypit because it seems as though there is a problem with the car every few months. I had a passat about 5 years ago too, and I spent so much money on that damn thing, I vowed never to get another VW. Now I am dealing with my girlfriend's VW problems...dagger...

Quote:
Originally Posted by Fl_bug View Post
I really wouldn't call it a moneypit because it really isn't. You're in the same boat as me, fixing the things the previous owner didn't do. Its really a great car once you get it to where it needs to be. Unfortunately, it just takes a while to get there but it will be worth it in the end.

I was in your shoes about to sell my car amonth ago, but then for one day, it ran perfectly and i had no issues with it and remembered all of the reasons i bought the ar in the first place. Unfortunately, i still stare at every Mazda 3 and Volvo S40 that passes, but i know i'll NEVER own one for the simple fact that its not a Vw, Audi, Porsche, Bently, Seat, ect

Ok, now to the problem. I highly recommend you just take it to a Vw Mechanic (NOT THE DEALERSHIP UNLESS YOU WANT TO PAY FOR OUTRAGEOUS LABOR RATES) near you. Here is a list of trusted local mechanics listed by state. They are TDI shops, but iirc, most of them will work on the gasoline engine ones too. They can inspect your waterpump and timing belt too.

I STRONGLY doubt its ever been replaced and now is the time for you to start saving up for you to get it fixed. I JUST dropped off my car to a local VW performance shop (with a lot of the cool people I've met at the local Wednesday GTG) and the total cost of mine was $427.17 for parts AND labor. Its not too bad if you find the right place.

To sum it up, take it to a shop first and then go from there.

Good luck and hopes this helps.
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Old 02-25-2010, 11:55 PM
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A good trick to check the water pump is to simply take the thermostat out and feel in the water pump cavity. If the impeller is loose or broken in half, it should be easy to feel. Another culprit of the fans not kicking on is the cooling fan control module. It doesn't throw a code when it goes out.The module is located on the driver’s side near the bottom of the radiator. You can also test the fans with a bypass wire.
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Old 02-26-2010, 12:03 AM
ptgRegistered Member ptg is offline
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OK, so here's what I've done:
  • replaced the coolant temperature sensor
  • replaced the a/c sensor
  • replaced the thermostat
  • flushed, burped, and refilled the coolant

I'm pretty sure that the car is still overheating because the upper radiator hose is very hot and the the coolant reservoir looks like it's boiling over a little bit. And of course, there is still no heat coming out of the vents.

The upper radiator hose is hot. The lower radiator hose is cool. Not sure about the radiator, but one of the fans was coming on last week, but neither of them are coming on now...when I turn the heat to HIGH and A/C and recycle air buttons both on.

Once I took the old thermostat out, I put it into boiling water, and sure enough, it opened and closed with no problems, so it's definitely not a thermostat problem.

My only guess now is that there is air in the system, like you said. I've been massaging the radiator hoses like crazy with the reservoir cap off and engine running, but I'm not sure how I know if there is still air trapped in the system or not? Can you explain to me exactly how you got the air out of the system? It seems as though this *may* be the problem or perhaps the radiator is clogged, but when I flushed the system, water came out of the coolant drainage with no problems, so a blockage is unlikely. The radiator fans are not coming on though, so perhaps the hot coolant is not entering the radiator?? I'm so very stumped here...

I appreciate all of the help so far!!!

Quote:
Originally Posted by wep300 View Post
I've been working through a bunch of overheating issues on my '99 2.0. Had it for a couple of months & am still sorting stuff out.

First question--is it really overheating, or are you getting a spurious flashing light? Ck your owner's manual, but I was under the impression that the coolant level sensor can throw the red flashing ligt--so if the sensor or wiring is bad, that might do it. A Vagcom check will tell you the actual coolant temp.

Does the radiator feel hot top to bottom?

Re: the thermostat, take the old one and put it in a pot of boiling water. Hold it off the bottom of the pot with a wire so you don't fry it. If you have a digital kitchen thermometer, stick the probe in the pot (off the bottom). T-stat should hold water when it's cold, and it will drain through when >87 C if a tstat is good. So even without a thermometer, should open in boiling water as long as you live below about 6500' altitude.

BTW, Prolly not your problem, but I had a heck of a time getting the air out of the heater core and lower radiator when I changed coolant. Lower radiator air was causing the fan switch to stay cold even though the coolant was hot. Finally ended up jacking up the right side of the car, massaging hoses, changing engine speed, and bleeding the lower radiator valve. Strange that there would be air low in the radiator, but there must be a baffle in the side tank to separate the upper and lower chambers.
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Old 02-26-2010, 03:48 PM
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Default Air...

I had the exact same symptoms when I had air. I had flushed the heater core and radiator with a hose and got goood flow, so I figured there was nothing plugged up. Problems I saw:

1) Fan wouldn't come on--my diagnosis was that the fan switch was not seeing any heat because of air. (Not sure what the inside of the radiator tank looks like, but there must be some kind of baffle in the middle to keep the coolant from short circuiting from the upper hose to the lower). I got that air out by opening the radiator petcock with the system under pressure. The first water that came out was cold, then there was a blast of air, then hot water. After that the fans came on.

2) Boiling in tank--I almost thought I had a blown head gasket because there was so much "boiling" going on. After I had done the air purging, that stopped. It was probably a combination of air purging and coolant boiling going on.

3) No heat--the theory was that the heater core was air bound. I had a helper run the throttle at 3000 rpm while I alternately squeezed the heater supply and return hoses. The heat came back, first only at high RPM. After some more burping, it's now on all the time.

I did the burping with the right side of the car jacked up so that the coolant reservoir was at about the same height as the heater hoses. Not sure why that should make a difference, but it seemed to.

The other mistake I made in flushing the system was not draining the block. I was only getting about 1/2 the coolant out of the radiator petcock, which led me to believe the radiator was plugged. After reading Bentley, it was obvious that I'd left a bunch coolant in the block and reflushed by pulling off the oil cooler hose to drain the block.

I've worked on a ton of cars (Saab & Volvo, mostly) in the last 40 years, and this one was by far the hardest to get the air out of.
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Old 02-26-2010, 04:03 PM
ptgRegistered Member ptg is offline
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Is the radiator petcock the same as the plastic drain knob located on the driver's side to drain the coolant?

Where is the "oil cooler hose" located?
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Old 02-26-2010, 05:25 PM
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Default Petcock, etc.

Just like the name "petcock"--must be my love of British cars. Yes, it's the quarter turn valve at the bottom of the radiator.

The oil cooler (on mine, anyway) is an aluminum block that sits between the oil filter and the engine block. It has two hoses & I just pulled off the lower one. Got some misc. gunk out of the block by flushing with a hose into the coolant reservoir and letting it run out of the lower (front) oil cooler hose.
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Old 02-26-2010, 11:03 PM
ptgRegistered Member ptg is offline
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Default broken impeller blade

Alright, so I took the thermostat housing cover off again, and reached inside to check the impeller blade. BROKEN. I couldn't actually see the plastic blade, but it felt like half of it was missing, so I guess the next step is to replace the damn thing.

I will report back.
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Old 02-26-2010, 11:19 PM
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Default Do a good flush

I found chunks of plastic here and there (from a long ago replacement, when I changed out my water pump, it had a metal impeller)

I'd change the timing belt tensioner as well when you change the timing belt.

took me about 8 hours to do timing belt & water pump, but I'm obsessive-compulsive
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Old 02-26-2010, 11:23 PM
ptgRegistered Member ptg is offline
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Yeah, I'm planning on changing the water pump, timing belt, and tensioner. I don't normally mess around with cars, so this could be a little bit of an event trying to install this thing. You got any recommendations as far where I should buy the parts? I've heard mjm autohaus, germanautoparts, autopartswarehouse....ebay?? I don't need the thermostat or any anti-freeze, as I already have these.
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Old 02-26-2010, 11:39 PM
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i had the same problem til i did the water pump. got better. then it over heated again i was like wtf. changed head gasket. ever since taking care of those two. i havent had a prob. hopefully the water pump will just fix it
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Old 03-17-2010, 01:01 AM
ptgRegistered Member ptg is offline
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Default broken impellar blade on water pump

So, to close this thread, I unscrewed the hose leading to the coolant thermostat and reached in to the left side, and felt the water pump. The plastic impellar blade was definitely split in half. I ordered the timing belt, water pump w/metal impellar blade, & tensioner from ebay for $120. Then I got my auto-mechanic to install the new parts for $300. I initially tried to do it myself using the following DIYs:

VWvortex Forums: DIY: Transverse Timing Belt, water pump, thermostat...

VWvortex Forums: DIY: Timing Belt And Coolant Pump Replacement on 2.0 AEG! Pics Inside!

BTW, you don't really need brand new engine mount bolts. My mechanic scoffed at me when I handed him the new bolts that I had bought from the dealership for $30 (4 bolts). To be honest, if I didn't hand him the G12, he probably wouldn't have used that either. I guess in a car with 105k miles, G12 or Dex-cool or whatever, they're all the same?

Anyways, I've attached a picture of the broken impellar blade.

Everything is running fine now. Heat again. No overheating. Everything good...for now. Appreciate all of the help.
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