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Coolant leak, water pump?

27K views 43 replies 8 participants last post by  DoseThemAll 
#1 ·
2003 1.8T GLS AWM Auto FWD, 89K

I found a coolant loss some day last week with only half of the coolant in the reservoir. Topped it off and runs good for a few days. Today, found a puddle of coolant on the ground, about 1/4 quart I guess. Drove a few miles and parked and put a big plastic box underneath. Immediately there were two drops then stopped. Checked it about one hour later, my god, it keeps dripping from the front. Jacked up the car and got underneath. The dripping is from what I believe is the crankshaft pulley in front of the oil pan. Also signs of dried coolant at the bottom of the oil pan and even the tranny oil pan. Is it the water pump leaking? The car has the original timing belt and water pump I believe.

Looks like a TB and WP job is ahead of me but I like to confirm it is the WP. Do I have to put the car in service mode (move the front bumper) in order to open the TB cover to verify? Any info will be appreciated.

Could it be the thermostat? I know the chance is low but still hoping...

Thanks...
 
#3 ·
Thanks Emry. I replaced the coolant flange last year. The leak is at the front somewhere above the crankshaft pulley because I see water drop at the bottom edge of the pulley which makes me think the water pump. Is there any coolant hose in that area?
 
#4 ·
There is a possibility about the water pump. How old is it?

I recall recently someone had the same problem and one of the hoses in front had a crack on it. It's a PITA to search the forum to find that post but at this time I suggest you inspect all the hoses in front of the engine carefully.

At the same time may be some one else could shed some more light on this for you.
 
#5 ·
Could it be the thermostat? I know the chance is low but still hoping...
Could be, but from your description sounds more like the water pump. And why would you be hoping for the thermostat? You are Past Due for the timing belt service and should have this done ASAP!! This will include your water pump and thermostat in addition to the timing parts. I don't know how new you are to your Passat but it has what is called an interference engine. This means the valves and the pistons use the same space and IF the engine gets out of time the valves and pistons Impact each other. Then you have Bent valves and you need to at a minimum re-build/replace the head. It is Much cheaper to just bite the bullet and do or have the timing belt service done.
There are DIYs here if you are mechanically incline and some very experienced members to help you through the project. Just remember, better to ask before moving forward if you come up with something you do not feel is correct to you do not understand.
One last thing, the Cheapest Deal on timing parts is not always the Best way to go. Refer back to interference engine.

Using G12 or G13 coolant when you are topping your coolant up?
 
#6 ·
You are Past Due for the timing belt service and should have this done ASAP!!
Second that. Although 89K miles is about the right mileage for changing the TB but the age of the belt is equally important.
In other words, your TB and water pump have been sitting there for more than 12 years (or more). The life cycle of a TB is around 7 years depending on the extreme weather condition. And water pumps go bad sooner than the belt itself. So your best bet is to replace the TB and pump yesterday.
 
#7 ·
Thanks 2002 and Emry.

I was hoping it is the thermostat because it is rather easier to fix. I had the car when it had 42K on it. Yeah I have always been using G12/13 to do the top off. I know I need to replace the TB/WP but was just hoping this leak is nothing major and can be fixed easily. It will buy me sometime to prepare for the TB job.
 
#8 ·
The water pump leaks down the front of the engine and will appear as coming from the crank pulley. The thermostat will leak down the side of the engine.
You need to change the pump and timing belt asap. I've had cars leaking for a month and then had the pump seize and start to burn the timing belt and I've seen others last for several months.
 
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#12 ·
Hi PZ,

Sorry for bothering one more time. Below are the kits from ECS ($205) and Blau ($242). Looks like Blau has more items in the kit then ECS, but I am not sure if those extras are necessary. What do you think? Thanks.

ECS Kit includes the following:
Timing Belt
Tensioner
Tensioner Roller
Idler Roller
Water Pump With gasket
Thermostat with O-ring (though it doesn't mention the housing but the pictures on their web shows it)
A/C Belt
P/S Belt

Gen II BLAU® VW Passat Timing Belt Kit For 1.8T I4 Engines
BLAU® INA Pre-assembled Base Kit Includes:
1 'INA Gates' Timing Belt
1 'Litens' Timing Belt Tensioner
1 'Litens' Timing Belt Tensioner Idler w/Bracket
1 'INA' Timing Belt Service Interval Sticker
Enhanced Additions:
1 'Graf' Water Pump w/ Metal Impeller and Gasket
3 Water Pump Bolts
1 Thermostat w/ O-Ring
1 Thermostat Housing
2 Thermostat Housing Bolts
1 'Flennor Gates' Power Steering Alternator Serpentine Belt
1 'Flennor Gates' AC Compressor Serpentine Belt
4 Serpentine Belt Pulley Bolts
1 Viton Front Crank Seal
1 Viton Camshaft Seal
1 Thread Locking Compounds
1 Anti Seize Compound
Blauparts Detailed Step-by-Step VW Passat 1.8T Timing Belt Instructions
Numerous pages and over 30 images of detailed step-by-step guidelines, including front bumper removal
 
#14 ·
No need for the seals or new bolts unless yours are corroded, stripped or worn. Probably no need for the thermostat housing unless you have a leak. On the 1.8T, I might have replaced 2-3 leaking thermostat housings versus 50-70 timing belts.
 
#15 ·
Thanks a lot. I will go with the ECS kit. I replaced the crank and cam seals when I did the timing belt for my Sienna. Later I thought it's really not necessary since they are not leaking and were in good shape. Taking them out was not fun, especially the rear cam seal on a V-shape engine.
 
#16 ·
For the crank seal, leave it alone if it is not leaking. These rarely fail...presuming you're not leaving that water pump leaking for a long time :eek:)

The camshaft seal can also be left if it looks good - it is far easier to replace than the crank seal, but if it is still good - don't mess with it.
 
#17 ·
Update -

First, thanks to all for the valuable information. I ordered the kit from ECS and got the job done during the weekend. The leaking is from the water pump, confirmed! Too bad the cam seal is leaking oil too, kind of bad since I can clearly see oil at the seal. I can also see lots of oil sign underneath the cam seal, on hose etc. That explained why I can still see oil drops on the floor sometime even after I replaced the valve cover gasket, oil leaked even worse before. Got a cam seal from nearby dealer because the kit from ECS didn't include seals. So replaced the cam seal, timing belt, water pump, alternator belt, AC belt and thermostat. I also cleaned the throttle body and the MAF sensor since I took them off anyway.

Opinions on timing belt replacement - since the engine has only a timing mark on the camshaft and a mark on crank pulley so I did the following.

1. Crank to TDC, mark the top center tooth (12 o'clock) on crankshaft and engine body.
2. Mark 2 teeth (3 & 9 o'clock) on crankshaft and belt.
3. Mart the belt on the camshaft mark position.
4. After took off the belt, copy the same marks to the new belt.
5. Before install the new belt make sure the crankshaft mark (I made) align with the mark on the engine body, align the camshaft mark.
6. Install the new belt. Align those marks to the marks I made on crankshaft and camshaft so there is no way you can make it wrong.

When installing the thermostat put some sealant on the housing to sit on the o-ring. I used Toyota FIPG (firm in place gasket) since I don't sealant handy.
I have a feeling that I should change the 4 bolts on the crankshaft pulley (harmonica balancer) which I didn't. But it should be fine, I think.
Hope this helps.
 
#19 ·
Thanks Tom for asking. I forgot to mention and yes, I replaced them. By the way, I noticed two issues after the replacement. The hood is not closing as smoothly as before. I have to close it really hard otherwise it won't lock. Another strange thing is the front driver and passenger side window is still rolling down automatically on one click but they won't go up by themselves and I have to pull the button all the way until they close. Don't know why.
 
#22 ·
Now looks like I got another issue which may require me to do the job again. The camshaft seal is still LEAKING! I am seeing one or two oil drops on the floor. Open the top timing belt cover and put my hand in and finger to the cam seal then oil is on my finger tip. It is a new seal from dealer. The old seal was not taken out nicely since I don't have a puller and the drill hole/screw method didn't work very well too. I finally took it off by using screwdriver, homedepot paint can opener etc. There is tiny bit of scratch but I think it should be fine. Lightly hammer the new seal in with a piece of pvc pipe. I thought it seated very well. Then why it is still leaking?

Thanks.
 
#24 ·
Hi gigi, I am not sure which one I am using. The part # is 038-103-085-C which I bought from a VW dealer. It looks like metal coated with rubber to me. It looks the same as the one I took off. Let me take a picture of the old one upload here.

I spent few hours to take off since I don't have the right tool. When install I put some fresh oil on both outer and inner surface and slightly hammer and drove it in with a hammer and a piece of PVC pipe. Might be it not seated properly since the diameter of the PVC pipe is slightly bigger than the seal hole. Can you please point me the instruction if there is one?

Thanks.
 
#26 ·
The bore in the head and the outside of the seal should be completely free of oil or anything else. (clean with solvent)

Have you scratched the camshaft, the bore in the head, or both ?
If only the bore is scratched, you might get away with using a sealant on the outside of the seal.
 
#27 ·
I don't think I scratched it although the way I took if off was not professional. I cleaned the camshaft and bore using shop towel before I installed the new one. I also checked for any scratch under a magnify glass. But I did lube the new seal with fresh engine oil on both inner and outer surfaces. I am going to take off the top timing belt cover and take a look. BTW, I didn't take off the valve cover for the seal installation. Was that a problem?
 
#29 ·
No matter what, I have to redo the job. But what could be the cause? I don't mind to redo the job but would like to fix the issue. Below are the causes I can think right now.

1. seal was not seated properly.
2. because I oiled the outer surface?
3. I scratched the shaft or bore or both.

I really appreciate if you guys could give me some info like what could be the cause for the leaking. Now it is leaking a lot worse than before.

Thanks..
 
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