Coolant leak/ Frost plug?

2000TDIJetta

Veteran Member
Joined
Feb 20, 2006
Location
Buffalo, MN
I have a coolant leak that appears to coming from between then engine and tranny. I cant see any thing leaking from the top of the motor. My question is: Is there a frost plug on the drivers side of the engine between the tranny and engine that could be leaking?
 

paramedick

TDIClub Enthusiast, Vendor
Joined
Jul 29, 2001
Location
Versailles, Kentucky
TDI
2015 Audi Q5 TDI
Nope.

Look to the coolant flange at the end of the head, or coolant temp sensor.

I have seen the hoses off the coolant flange and EGR cooler develop leaks. Look carefully there.
 

2000TDIJetta

Veteran Member
Joined
Feb 20, 2006
Location
Buffalo, MN
paramedick said:
Nope.

Look to the coolant flange at the end of the head, or coolant temp sensor.

I have seen the hoses off the coolant flange and EGR cooler develop leaks. Look carefully there.
I looked at that flange and see nothing running on the top of the tranny or around the flange. the egr cooler is on the back side of the engine and i also didn't see anything from that area.

It is leaking from inside the bellhousing. From the bottom of the engine, it is running out of the clutch area inside of the bellhousing. I don't see anything running on the outside of the tranny.
 
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hanother

Active member
Joined
Nov 21, 2009
Location
Kalamazoo, MI
TDI
2012 PASSAT TDI, 2010 JSW
Hi maybe this could help.

I just patched a leak in my hose running to the egr, it had been rubbing on the larger hose below it. It just rubbed a tiny pinhole in it. I was loosing about a cup of coolant every other day.

The hole in the hose was above the transmission. Coolant was running down the bellhousing.

I cut the hose and put a brass hose barb in it.

worth a look!

I had to use my hand, running it along the hoses after it was hot to find the leak.

HT
 

2000TDIJetta

Veteran Member
Joined
Feb 20, 2006
Location
Buffalo, MN
paramedick said:
I'm confused. Please show me. This is a pic from a ALH block in my garage.
Thanks for the pic. The one i posted is what i found online. apparently the older blocks are different?

What is that small hole/plug on the to the left of the cylinder a few inches above the crank?

Thanks for your help.
 

2000TDIJetta

Veteran Member
Joined
Feb 20, 2006
Location
Buffalo, MN
hanother said:
Hi maybe this could help.

I just patched a leak in my hose running to the egr, it had been rubbing on the larger hose below it. It just rubbed a tiny pinhole in it. I was loosing about a cup of coolant every other day.

The hole in the hose was above the transmission. Coolant was running down the bellhousing.

I cut the hose and put a brass hose barb in it.

worth a look!

I had to use my hand, running it along the hoses after it was hot to find the leak.

HT
Thanks, i will take a closer look at that hose. weird thing is I don't see anything running down the outside of the bell housing, it is running out of the bottom of it from inside it.

Is there some way the coolant can run into the top of the bell housing and then back out at the bottom?
 

Nacnac

New member
Joined
Sep 16, 2010
Location
Georgia
TDI
2000 VW Jetta
2000TDIJetta:
What did you ever find that was causing your leak? I seem to have the same leak as you and other than pulling the transmission, which I have yet to do I cannot find anthing. Like you said it is leaking from where the transmission mates to the engine. Does anyone have any suggestions?
 

Curious Chris

Top Post Dawg
Joined
Jun 11, 2001
Location
Pineview GA
TDI
Jetta Wagon 2003 RIP Rockford IL
Thanks for the pic. The one i posted is what i found online. apparently the older blocks are different?

Thanks for your help.
Yes pre-1999 on Jetta/Golfs had a different engine. The biggest hint is the location of the oil filter: pre-1999 metal oil filter hanging off the engine about 1/2 way to the bottom that you unscrew and replace with a new metal filter, post 1999 the oil filter is a cartridge filter located in the front center of the engine and comes out the top.
 

TDInda315

New member
Joined
Dec 4, 2010
Location
Marcellus, NY
TDI
2000 Jetta 1.9L
Yep, I just discovered the same symptoms in my 2000 Jetta, about 203k miles. Took the stone guard off and was just dripping coolant right where the engine and tranny bolt up. The housing where the driver-side axle goes into the transmission is all wet (dealership did replace drive axle seal about a year ago).

It showed up a couple of weeks ago and has been bugging me ever since. Coolant is coming from somewhere, but I can't find it :confused: Top of the engine and tranny are dry. I'm losing about a cup every other day also. Clutch feels stickier, too (but this might be imagined - or something else!)

Connections at EGR cooler, oil cooler, and back behind the temp sensor are all dry. If it stays hot, it's fine. But begins to leak when cooling down (like a seal is contracting and opening up).

I did a red-neck cleaning of my intake manifold and cleaned the tubes of the EGR cooler with solvent, hot water and a wire hanger last summer and I just replaced the thermostat, and the glow plug bridge (to solve a P0380 MIL code). Other than that, it's been just filter changes and timing belts.

Was 2000TDIJetta's resolution a leaking hose above the transmission? If so, I'll just take another crack at it and check the whole length of hoses. Thanks!
 

TDInda315

New member
Joined
Dec 4, 2010
Location
Marcellus, NY
TDI
2000 Jetta 1.9L
Closing the loop on this one: I finally discovered the source of this leak. The O-ring around the temp sensor/switch. Didn't find it until the engine had cooled down for an hour or two in the garage. I started hearing a faint hiss and tracked it down to the temp sensor. An hour prior, I had eliminated this as the source of leak because it was dry (when hot and the O-ring expanded). I plunked down $2.92 for a replacement O-ring at Romano's in Fayetteville, had a nice chat with another TDI guy at the counter about glow plugs and went about my merry way.

So, I'll concur that tracking these leaks down is tedious and dependent on the temperature of the engine.
 

JETaah

Vendor , w/Business number
Joined
Jan 18, 2001
Location
mi 48836
TDI
96 B4V, 1999.5 jettaIV,2005 BEW Beetle
refering to the picture by Paramedick....

"What is that small hole/plug on the to the left of the cylinder a few inches above the crank?"

That is a plug to the oil galley that feeds the crank, rods and piston spray nozzles. There is one on the opposite end of the block as well.

It is easier to find leaks when you inflate the cooling system and put your ear to it while the engine is not running. When I change a water pump during the timing belt maintenance or anything that requires finding a leak I fill the system with about 15 PSI of air to see if the pressure drops. I would hate to get the timing belt all finished just to find that the oring could not seal for some reason so I test it right after the water pump is mounted.

Another leak that is hard to trace is a freeze plug which is on the cylinder head of the ALH behind the inner timing belt cover above where the TB tensioner stud screws in. Normally these don't rot out but on one car that I worked on the coolant had been mixed with another incompatable type and the reseroir had a scum that had the consistancy of scrambled eggs. The on the outside the leak was the size of a pin hole but on the inside of the freeze plug it was totally pitted.
 
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