Hellish coolant leak

borntofli

Well-known member
Joined
Jul 23, 2018
Location
Texas
TDI
1998 jetta tdi
I just replaced all the coolant hoses on my 98 tdi... Replace all of them, if 1 is leaking , the others will soon follow... idparts has them all for cheap...... get rid of those spring clamps also..they suck when you need to remove one....
 

KLXD

Top Post Dawg
Joined
Aug 22, 2009
Location
Lompoc, CA
TDI
'98, '2 Jettas
Not if you have the right tool.

I'm going on the assumption that the OP is not an idiot and this is a serious thread. If he can't find that big a leak, even in the rain, it must be going out the exhaust. In other words, the heat exchanger.
 
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Abacus

That helpful B4 guy
Joined
Nov 10, 2007
Location
Relocated from Maine to Dewey, AZ
TDI
Only the B4V left
KLXD is correct, with the right tool they’re easy. Think of them as constant tension clamps, which automatically adjust for temperature. I just replaced the worm drive clamps on a B4 with the originals from my stash because the coolant hoses were leaking when the car warmed up.
 

oilhammer

Certified Volkswagen Nut & Vendor
Joined
Dec 11, 2001
Location
outside St Louis, MO
TDI
There are just too many to list....
They are for sure superior, and NOT difficult at all to deal with so long as you have the correct tool. Plus, the clamps that VAG uses are really the best of that type, better than any other manufacturer. Sturdier, easier to get a hold of, and do not have that stupid tab to hold them open.
 

JETaah

Vendor , w/Business number
Joined
Jan 18, 2001
Location
mi 48836
TDI
96 B4V, 1999.5 jettaIV,2005 BEW Beetle
KLXD is correct, with the right tool they’re easy. Think of them as constant tension clamps, which automatically adjust for temperature. I just replaced the worm drive clamps on a B4 with the originals from my stash because the coolant hoses were leaking when the car warmed up.

This is definitely a sore spot (one of them) on the Frost heater installations. I almost always find those weeping at the joints with screw clamps.
 
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Chris_TDI_98

Veteran Member
Joined
Jul 19, 2012
Location
Hartford, CT
TDI
1998 Jetta TDI 1.9L mk3 1Z AHU
I drove car up on curb, then poured a gallon of water into reservoir sphere.
I saw water gushing on the back of the engine, ie the side of the engine which is facing the firewall.
It’s dark down there and very tight to manoeuver a hand and it’s well blocked by the subframe from underneath.
Will try to post pics, stay tuned.
What could possibly be leaking so much coolant, down there near the firewall!?
 
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Chris_TDI_98

Veteran Member
Joined
Jul 19, 2012
Location
Hartford, CT
TDI
1998 Jetta TDI 1.9L mk3 1Z AHU
Any of the three frostplugs:
is there a 110V electrical cord in sight?
There isn’t a 110V electrical cord in sight.
We had below freezing weather while I was away for a month and the car wasn’t driven ie didn’t get warmed up, and the coolant was higher in water than coolant, I presume one of the frost plugs might have gotten pushed out due to the freezing expansion of the too-watery coolant. :( Now how to fix? Is the block steel or aluminum? Weld something over the possibly destroyed block heater plug hole?
 

Vince Waldon

Top Post Dawg
Joined
Apr 25, 2009
Location
Edmonton AB Canada
TDI
2001 ALH Jetta, 2003 ALH Wagon, 2005 BEW Wagon
Well, it sounds like the frost plug may have done its job and saved your engine.

The block is cast iron... not something easily weldable, even if you could get to it. :)

The fix, if the issue is a frost plug, is to finish removing the frostplug that is partly pushed out, clean the hole, and then install a new one.

Depending on which one is actually leaking hammering in a new one can be tough with the engine installed... you can drop the engine or simply install a block heater, which will seal the hole but installs with a screwdriver.

All of this starts with confirming the actual site of the leak... with the new information that you were running weak coolant it's also a possibility that the block is cracked... the frost plugs can only protect so much.
 
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Chris_TDI_98

Veteran Member
Joined
Jul 19, 2012
Location
Hartford, CT
TDI
1998 Jetta TDI 1.9L mk3 1Z AHU



The arrow shows the direction of water flowing out of the rear of the engine, it’s gushing out toward the firewall.
 
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Vince Waldon

Top Post Dawg
Joined
Apr 25, 2009
Location
Edmonton AB Canada
TDI
2001 ALH Jetta, 2003 ALH Wagon, 2005 BEW Wagon
The interwebs are not going to be of much help narrowing down exactly where your leak is at this point.

Best bet is to be *under* the car with a strong battery-powered light while someone adds water, and the first thing to identify while you are under there is the three frost plugs, using the picture in the previous post as a guide.

If it's an actual crack in the block it literally could be anywhere back there unfortunately.

Sent from my Moto X Play using Tapatalk
 

Chris_TDI_98

Veteran Member
Joined
Jul 19, 2012
Location
Hartford, CT
TDI
1998 Jetta TDI 1.9L mk3 1Z AHU

This is the block picture Vince posted a link to above.
Thanks Vince!
Will get out under it in the morning first thing, with smart phone camera on selfie stick up in there trying to confirm a missing frost plug. The gush itself looks cylindrical so I’m saying some Hail Mary it’s just a pushed-out freeze plug where I can install a block heater.

Question, are all 3 spots able to take a block heater instead of the oem basic non heating plug?
 
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TDIDaveNH

Left Lane Coal Roller at Large
Joined
Feb 17, 2009
Location
North Conway, NH
TDI
1997 Passat TDI x2 1984 Buick Century 4.3 diesel
All three spots will FIT a plug heater but only one spot is ideal, the one on the driver's side due to of course the turbo being in the way for the other 2. I was also thinking of the hard coolant pipe, right where you drew in the red arrow is the same spot they rot out from first and it's the hardest to see. I was loosing coolant for a while and could not track it down. My coolant pipe had some rust on it but it wasn't hideous. Lo and behold, the backside of that corner just below where the hose comes in from the coolant sphere was rotted and weeping. I suspect if you find all three freeze plugs intact and unmoved, that is the spot I would focus my attention on next.
 

Chris_TDI_98

Veteran Member
Joined
Jul 19, 2012
Location
Hartford, CT
TDI
1998 Jetta TDI 1.9L mk3 1Z AHU
Is the “hard coolant pipe” you refer to, is it the black narrow one on the US driver side (left side) of the engine, or is it the one connected to the EGR cooler?
 

Chris_TDI_98

Veteran Member
Joined
Jul 19, 2012
Location
Hartford, CT
TDI
1998 Jetta TDI 1.9L mk3 1Z AHU
Some more newbie questions, sorry:
1. Where are all the coolant temp sensors located on the mk3 TDI ? (Besides the sensor on the spherical coolant reservoir, and the sensor on the engine coolant flange?)
2. How to test these coolant sensors with a digital multimeter, ie how many ohms across which terminals ?
 

Steve Addy

Top Post Dawg
Joined
Aug 7, 2002
Location
Iowa
TDI
97 Mk3
Is the “hard coolant pipe” you refer to, is it the black narrow one on the US driver side (left side) of the engine, or is it the one connected to the EGR cooler?
The cooling system on these is really easy to figure out, just trace the hoses you can see. The coolant pipe is easy to find, it runs from one of the heater core lines around the front of the engine and down to a hose going to the WP....

Steve
Mounted to the left side of the engine at the coolant flange bracket and then turns in the front of the engine and heads to the WP near the oil filter stand.

Steve
 

Chris_TDI_98

Veteran Member
Joined
Jul 19, 2012
Location
Hartford, CT
TDI
1998 Jetta TDI 1.9L mk3 1Z AHU
Here’s the link to the photo album of this coolant leak.
I’ve added some pics of the back side of the engine, taken today with phone on selfie stick.
Tell me if these are close to the right area of the block where the freeze/frost/core plugs are!?
Trying to confirm whether it’s either :
A: freeze plug missing/pushed out from freeze expansion of the watery coolant, or
B: rusted out coolant pipe.
https://photos.app.goo.gl/YL8oo6mppfkwbCjSA
 
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Chris_TDI_98

Veteran Member
Joined
Jul 19, 2012
Location
Hartford, CT
TDI
1998 Jetta TDI 1.9L mk3 1Z AHU
Thanks Arnie, that pic is so blurry and I have so little experience working behind the engine that I wouldn’t have been able to put 2 and 2 together.

I’ll pay for help from experienced TDIClub forum members in or near my area, Hartford county, Connecticut, interested and can repair this?!
I have the KAT brand vw tdi 1.9L compatible block heater ready to install there.
I can borrow a pair of ramps to get more space under the car.
I’ll pay gladly to get this freeze plug coolant leak fixed!!!
Any suggestions on what to do to solve this, even a temporary fix, are welcome!!
 

ToddA1

Top Post Dawg
Joined
Aug 3, 2011
Location
NJ 08002
TDI
'96 B4V, '97 B4 (sold), '97 Jetta (scrapped)
If it’s a freeze plug good luck, without pulling at least the turbo, dp and axle. There isn’t a lot of room to work, back there. I foresee a lot of struggling and cursing.

-Todd
 

Chris_TDI_98

Veteran Member
Joined
Jul 19, 2012
Location
Hartford, CT
TDI
1998 Jetta TDI 1.9L mk3 1Z AHU
If it’s a freeze plug good luck, without pulling at least the turbo, dp and axle. There isn’t a lot of room to work, back there. I foresee a lot of struggling and cursing.
1. If we’re unlucky it’s the center freeze plug behind the turbo,so would there be a temporary fix possible, such as a blob of JB Weld two part metal epoxy!?
2. If we’re lucky it’s the left/driver side freeze plug, I’ve read online this left/driver side freeze plug is accessible directly without pulling turbo or downpipe or axle, able to install block heater where the freeze plug was.
 

iluvmydiesels

Veteran Member
Joined
Nov 21, 2015
Location
phila area
TDI
AHU
what i do in these situations, is do the outside work myself. remove such things as turbo, oil line(s), exhaust and such. as a shop will want to be able to get free access to the area they are working on/at. if its one freeze plug. if it happens to be more than the one, you have to prep areas. otherwise the bill will reflect the removal and reinstallation of parts. doing only part of the prep pre-shop work isnt a good idea. wont help out, they wont reward you for partial prep-work.
then get ready to tow car to shop, after they work on it, install plug(or more), tow car back home to finish job.
dont forget to cover/plug openings such as oil openings, etc.
 

Chris_TDI_98

Veteran Member
Joined
Jul 19, 2012
Location
Hartford, CT
TDI
1998 Jetta TDI 1.9L mk3 1Z AHU
A video showing how to install the KAT block heater.
It uses a screw which when tightened causes a butterfly to open and hold it in the freeze plug hole.
The block heater fitting the vw jetta mk3 a3 tdi 1.9 is KAT 11420.
https://youtu.be/U100x8rF4xg
 
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Vince Waldon

Top Post Dawg
Joined
Apr 25, 2009
Location
Edmonton AB Canada
TDI
2001 ALH Jetta, 2003 ALH Wagon, 2005 BEW Wagon
That's the 5 minute part of the job, once the turbo is out, the old plug has been removed bit by bit (depending on how rusted out it is it come apart in pieces) and the hole cleaned and prepped.

Because it's rusting out there's no temporary blob of anything that will patch it. The system is hot and under 15 psi of pressure, even if the plug itself wasn't rusting apart.

There's no luck involved: time to roll up the sleeves, pour some more water in there to confirm the location of the leak (prime suspect: the frost plug directly behind the turbo where the rust trail is and where water has clearly been washing away the oil from whatever is leaking oil back there) and fire up the wrenches. :)

Any attempt to binder-twine it together will absolutely leave you by the side of the road at the worst possible time. :) :)
 

oilhammer

Certified Volkswagen Nut & Vendor
Joined
Dec 11, 2001
Location
outside St Louis, MO
TDI
There are just too many to list....
That's the 5 minute part of the job, once the turbo is out, the old plug has been removed bit by bit (depending on how rusted out it is it come apart in pieces) and the hole cleaned and prepped.
Because it's rusting out there's no temporary blob of anything that will patch it. The system is hot and under 15 psi of pressure, even if the plug itself wasn't rusting apart.
There's no luck involved: time to roll up the sleeves, pour some more water in there to confirm the location of the leak (prime suspect: the frost plug directly behind the turbo where the rust trail is and where water has clearly been washing away the oil from whatever is leaking oil back there) and fire up the wrenches. :)
Any attempt to binder-twine it together will absolutely leave you by the side of the road at the worst possible time. :) :)
I agree, but have you seen the car in question? All his other threads, his pics, seriously the car is barely an organ donor. The turbocharger will be a pain to remove, what isn't a greasy mess with be rusted stuck with things breaking. The block is likely a big lump of rust, it'll certainly need ALL the plugs replaced. Is *that* car really, honestly, worth the effort? :confused:
 

Chris_TDI_98

Veteran Member
Joined
Jul 19, 2012
Location
Hartford, CT
TDI
1998 Jetta TDI 1.9L mk3 1Z AHU
Is *that* car really, honestly, worth the effort? :confused:
I have no choice, I have no other car, I can’t afford buying another car right now, I must learn how to remove the downpipe and turbo and any other parts in the way by referring to guides and kind advice and even actual in-real-life mechanical help from TDIclub forum members.
 
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