Stranded with Coolant Leak -- Bypass Water Filter?

Hi everybody, while travelling I experienced a major coolant leak and loss of the majority of my coolant . Thankfully I was close enough to a truck stop that I was able to coast into their lot just in time. Engine seems ok.

One of the diesel techs took pity on me and helped me. We found that one of the smaller coolant hoses had somehow (maybe I ran over something?) migrated into the cooling fan and had been gashed. In attempting to remove this hose at the bottom end we broke the male fitting that the hose mates with clean off. The component it was attached to appears to be a filter housing. It is maybe 5" square and it's directly below the oil filter.

Our "solution" was to bypass it by connecting the hose that flowed into that housing straight to the (I think) water pump. Basically we just deleted the water filter.

Filled it up with tap water (I know...) and brought it up to tempt, topped it off, and she ran great all the way home (150 miles). The tech obviously knows his stuff, but he's not a VW TDI guy. So I want to know what you guys and gals think. I won't have an opportunity to work on it for a week. Will it be o to drive as is till then? I'd rather not put high dollar vw coolant in it now just to have to buy anther round when I fix it.

Whatcha think? Thanks in advance!

Your post may open a large can of worms, but I am curious. I believe the item you are talking about is the engine oil cooler/heat exchanger. If you drive gently I don't believe you will hurt anything seeing as this is not the middle of summer and you you don't live in the desert. I am sure there will be guru's reading this post very soon, and then we will all know...

That story is of the very few with a happy ending. The repair done was spot on, sound thinking.
You can operate the car indefinitely like that, but I recommend repairing the broke bits and put it back how it was. Not sure what they call that box (oil/water cooler?) but it is a simple plumbing piece that allows the oil and coolant to share temperature. It helps with warm up and helps keep the oil from getting overly hot. Oil does double duty as lubricant and coolant.

I will share my experience from this past winter in my 2003 TDI.

I was accelerating onto the highway around 10pm at night. As I hit speed I see a cloud of white smoke out the back. It dissipates and I keep rolling thinking I might have to look at some hoses when I get home. It was running fine. A bit down the road the coolant light starts beeping and flashing. I pull off the highway and take a look. Definite coolant leak was noted by the smell but could not really see it. It was 20F or maybe less out. I get back in thinking its only a bit of coolant as the gauge wasn't showing it running hot. I drive away and the coolant temp gauge is no longer operating and reads like a cold car. I get down the road and pull off, buy a gallon of distilled water and top it up. I then head down the road again and the temp gauge again stops working. I took it easy on the highway on the way home and put it in the garage. In the morning I go out and see that the clip that holds the CTS in had been damaged (probably from the vac pump oil leak above it degrading it) and had allowed the CTS to pop out and drain the coolant. I put it back together with a new clip, refilled the coolant and all has been good since.

The take away might be that these engines run pretty cool. If you've ever wanted it to warm up quickly in a winter climate and realized that doesn't happen you might already be aware. I suspect the flow of cold winter air helped my situation as well.

Thank you so much for the replies everyone! Turns out you are all correct. I'm at VW getting parts numbers now, and it is indeed the oil cooler. I must have found a respectable dealer because they are telling me the same--that it should be replaced but it is no rush while it is still cool outside. Easy highway driving, watch the guage, should be ok.
Sounds like I owe that diesel tech a 12 pack or 3.

Of course I trust you guys' advice over the dealer any day, but it's good to know everyone concurs.

This place is the best! CHEERS!

When you run out of coolant the temp gauge will quit working because there is no coolant in the system anymore to transfer heat to the temp sensor.

I had a coolant leak on my old Mercury Vomit and sure enough just as the cooling system was devoid of coolant, the temp gauge would start heading to zero which meant it was time to put coolant in it ASAP.

http://auto.howstuffworks.com/1960-1963-mercury-comet4.htm

You could probably go till the end of time with the oil/water cooler bypassed and wouldn't hurt a thing. Since VW put it on there, you might as well make it right, though.

Yeah, I agree. Parts aren't too bad for this repair. I'm going to finish out this Spring break then later wait till a shade tree weekend.

I am glad to hear it was a simple fix that won't hurt the engine if run without immediate replacement. TDIClub has saved me countless hours and many dollars even to this day. I still learn new things about my TDI even after 8 plus years of ownership.

Nevada_TDI said:

I still learn new things about my TDI even after 8 plus years of ownership.

Click to expand...

Me too
The day I don't learn something will be the day 6 guys are carrying me away.