This is a fastener-by-fastener description of how I diagnosed and repaired a slow coolant leak as a result of a bad coolant hose flange on a 2001 VW MKIV Jet…
This is a fastener-by-fastener description of how I diagnosed and repaired a slow coolant leak as a result of a bad coolant hose flange on a 2001 VW MKIV Jet…
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I’m glad it helped. Yes, I was a little confused about those two different names until I reviewed an article done on wikipedia explaining all the different models and manufacturing history. Great resource.
I have a 2000 1.6L NA Volkswagen Jetta (although it’s called Volkswagen Bora over here) and it has the same kind of leak, this video explains everything clearly on what I’ll have to do. Thanks.
What you did to replace the head goes beyond anything I showed here. Nevertheless I’m glad it helped. Cheers!
I have a 2000 1.8T beetle and mine has a rubber oring. I just rebuilt the engine because the oil pickup tube was clogged up. Damage to head. Cam bearing destroyed…. thanks for your help…
Thank you.
Great Job! Very well explained too. Thanks !
Yes, it’s possible, but of course not the only possibility. When coolant level drops low, sometimes the coolant temp sensor can give spurious data. I would start by refilling with distilled water and burping the system, then restart the engine and look for a leak. If you have access to a pressure tester that could be done, too. If you do isolate a coolant leak then I would fix that, and hope that all is repaired with that. Good luck.
I just did job and I used a oem housing list was 28 bucks p/n 06a-121-132the o-ring is different from aftermarkets it has like 6 raised areas built in around o-ring and I used a little rtv blue around o-ring and tighten up around 10 foot lbs and flushed cooling system with g-12 vw coolant p/n g-013-a8j-1g 20 bucks . no leaks and all good
I don’t remember whether it was on the inside or the outside, but I would try to reproduce what you had before you fix it. I saw a set of still shots where a guy used RTV, and it seemed to work for him. But the dealers don’t normally use that — I asked my dealer and he said they don’t do that. I also wondered if a tighter torque would be better, but I didn’t find anything to support that either. Presumably there is a risk of breaking the plastic or distorting the seal. Thanks for your remark.
Im doing same job next week mine is seeping out coolant down the flange housing and down the head gasket down to bottom of transmission .im going to use a small about of rtv black around flange seal so I wont have to redo.I have a question on the rear 10mm nut is that metal line with the notch in it slide behind nut then tighten to 7 foot punds? i think so ? thank for your video and input.
PLEASE I have a 1999.5 jetta same engine but AEG,I had my A/C / fan on on number 1,while sitting in mcd’s smoke/vapor poured out my hood and out my vents,my temp guage didnt go up,my coolant light when on followed by a beep to warn low coolant.My anti freeze had spilled out.It is coming prominently from the back of the engine area,where the mortor oil cap would be but the bottom(refernce),not the top,just that generalarea but the bottom somewhere im guessing,Could it be this flange you replaced?
Thanks for the compliment. Unfortunately I have no experience with the transmission on this vehicle. Yes, a reasonable first step would be to check the trans oil level, and inspect the oil for debris or color change. You might get a more detailed and qualified response if you were to search out a VW forum. Your problem sounds serious, I hope it can be fixed.
tx very much you are the only calm and very detailed adviser that i so on youtube!!!!
now let me ask you how do i change the transmission oil please.
a have this weird problem with my jetta 1.8t 2002 she doesn’t go revers and she has some difficulties when change the shifts from 1-2-3 before when the engine wash hot the reverse was working now is not doing that even if is hot …. pls if u have the time to tell me if can be the oil.
tx and do what u doin coz u are the best in that!!
Yes I totally agree, the comments are a place where I often learn more than in the primary video. Thanks for your note. Regarding the dust everywhere, I usually take a rag with a little brake cleaner and wipe it down. If I am opening critical passages like rocker covers or intake manifold, I usually take a vacuum with a small head, removing dust before so it doesn’t fall into areas where the engine can be damaged. I try not to spray sensors or wires with any liquid.
Great video, thank you for being so precise, simple and clear. Do you have any suggestions for cleaning the the area prior to taking apart? Don’t expect a car to be pristine but ours is very dusty, grimy and it would be easier to see and work on things to start if it looked more like yours. But I don’t want to create more issues by taking a hose to it all or anything. Also thanks to people like @phishphinder23 from me too, it is so helpful to read others experience as well.
I’m glad it helped. Thanks for the feedback.
thanks for making videos like this one. .
helps a lot. .
Your compliment today was more than enough. Thank you back!
Man if I could just find away to pay you for helping me fix my car basically haha man I did this and have no experience on cars so well explained and guided thanks a lot saved me a lot of money (:
mine was leaking in the same place on my tdi, didn’t have to move so much parts like you did though.
Same part went bad on my 91 MKII Jetta, nice to see that some things don’t change. Maybe VW will get around to it someday!
I went to the local VW dealer — costs more but they had it in stock and there was no concern about it being suboptimal.
Any suggestions from which site to buy the flange and O-ring? Ive checked with some local automotive stores and they can’t get ahold of them.
Thanks for coming back to record your experience and to offer more practical advice. Guys like you make the thread that much more valuable.
2001 2.0 Jetta, Same leak, lower back side of flange was cracked out pretty good. Replaced with new part thanks to vid. All in all 1.5hr job. I kept true to G12 coolant. Came back to say thank you so much for the DIY. Very straightforward and clear. Tips: plastic clips and covers are very brittle, BE CAREFUL! Also, CTS gasket was pretty burned recommend replacing no matter what. New Flange gasket without sealant seems to be holding up just fine. Thanks again!
I tried to look it up for you on Alldata but they don’t have a diagram and I don’t have access to the car now. Of course the PCV valve connects the valve cover to the intake manifold, allowing blowby gasses to move from the valve cover back into the intake based on relative pressures. I guess you could call it a PCV hose, but it may not have a specific name. I don’t remember if there was another vacuum line but if there was it might be for some peripheral device.
what is the name of the hose that connects to the pvc heating element?
That’s good information, thanks for posting it here.
Excellent guide. I’ve had to replace the flange last night myself so thanks for your video guide and all good tips in it. This is the second time within last few months the coolant flange is replaced in my 2001 VW Golf. The original part started leaking and I had it replaced with non-OEM (Made in Taiwan) part, which wasn’t made to fit the temperature sensor all too well. There is a flow in the knock-off part temp sensor socket profile I’ve noticed. Thanks again. Great guide!
That’s a great point. Whenever I see a plastic flange, I roll my eyes with memories of misadventures that happen indirectly, usually when trying to fix something else. At least you can retap a steel hole, but trying to replace plastic parts can be a more frustrating challenge. Thank you for your comments!
Yes I’ve had to replace this on each of my Golf’s. My flange looked just like that one. And on one of the cars, the studs had been badly re-tapped and I had to re-tap them to 8mm and bore out the flange’s sleeves to get it to accept the 8mm allen head bolts. What ever you do, don’t even think about trying to backflush the heater core. The plastic outlets will snap off at the slightest movement of the hose. When this happened to me, I had to construct a heater core bypass apparatus.
And thank you back! Inadequate burping is by far the commonest (possibly serious) problem when a cooling system is opened. Some engines, like the GM 5.3L, have a coolant bleed hose, but others rely on their mechanics to follow a safe protocol.
Thank you so much! This video helped a lot, I would not have known about burping it. P.S. I hate this car… It love my money.
In retrospect I should definitely have done this repair sooner. You don’t usually see much coolant on the ground, since hot coolant mostly evaporates away and it only leaks when the engine is running. Even reservoir levels can be misleading because air pockets inside the coolant jacket lead to underestimation of coolant loss. If left too long you may see a CEL for coolant temp sensor, strange idle RPM’s, and poor coolant flow from ineffective pumping. Thanks for your comment, good luck!
you are awesome! really good video!! a lot of details! I may need to do it. I have a vw golf MKIV and I noticed some cooalant almost in the same place where you had, not so much, really a few of it, the level of cooalant is also stable and the engine doesn’t overheat. However I may try to do it and check just in case.
Thanks, Troy. Nice to meet you, and thanks for the sub.
Loved the great detail in this video! Really good! Thanks!
What a kind remark, thank you.
You’re a very caring mechanic. I was watching how you carefully removed and set aside other parts to the car. Thank you for becoming a great mechanic…its not many of you out here.
Yes. Steel wasn’t perfect, but I’ve never seen a steel flange fail so consistently. By swapping to plastic they improved fuel consumption and production cost at the expense of durability. New car buyers don’t usually care about that because normally they buy a new vehicle every four years or so.
Thats exactly were its leaking on my jetta. Is this a common problem on them
I hope it goes well for you, good luck! Of course there is always a chance of misadventure with auto repair, but without risk it wouldn’t be so much fun. I was just watching another video by my good web mechanic friend, briansmobile1. There is a specific mindset, a ‘Zen’ if you will, that I’ve always aspired to.
Excellent video, thank you very much. It was very . . . entertaining. 😉
I need to do this repair this afternoon, and you probably just saved me at least 30 minutes of assessing things and figuring it out, with bonus peace of mind knowing that it’s as simple as I thought. I think I bought too much coolant, though. Maybe they’ll take back the unopened one.
I’m glad it helped, thank you.
thank you for making this video it helped me out a lot and saved me an extra headache.
You may need to swap over a sensor – it should be easy. I would drain the coolant down below the level of the bottom of the tank first to avoid making a mess. You’re doing the right thing by replacing it.
Spelunkerd: is there anything specific to do to replace the antifreeze tank on a mk4? Mine is slightly damaged where it’s generating a small leak.. I ordered a new one. thanks in advance for any advice.