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Acquired a 964 and am doing some oil line replacement from the tank back. While I had the rocker off I decided to look at the lines to the front cooler. This is what I found:
I was quite taken back to see the connections done by hose clamps. While this fix by the PO seems to not be leaking I was curious on what others think about ignoring this or fixing it with crimped hose ends.
While maybe not appearing original or stock in components the only real variance from original equipment is the fact that non crimped ferrules or ends were replaced with
off the rack clamps ..
The replacement braided line appears to be of comperable or better than original cloth material and the entire setup is clamped restrained and without apparent leaks .
I would likely go on to some area not addressed this looks handled , if the non original appearance offends your sensibilities , have at it … Bert
What’s a realistic pressure rating for those clamps and what kind of pressure does the oil pump put out. I have to think it’s high and obviously very hot so this would make me concerned and I would have it on the short list to change.
To put it a different way, if clamps are an acceptable alternative to crimped ends then why did the factory go to extra lengths to crimp the ends? It would certainly cost less to buy hose in bulk with no crimped ends and clamp it together at the factory I would think.
Last edited by Spyder_2011; 06-15-2024 at 03:09 AM.
If it were my car I would take those lines to a hydraulic shop and have them properly crimped on.
If one came off you would lose all your oil pressure very quickly and that could lead to a crash or catastrophic engine damage.
If you want, you can throw a strong zip tie around them for support...but as long as the hose clamps don't vibrate lose...aka unscrew themselves, if it's not currently leaking, it'll be fine.
If it were me, I'd redo the lines. But i wouldn't re-use that hose. Buy new hose from elephant and crimps from belmetric (see oil line madness for reference), and as Dave said above have a hydraulic shop crimp the hose on correctly.
The reason to replace the hose is that you'd be doing a ton of work to swap, and the likelihood is those hoses get damaged when you take the fittings out of the ends. So they will most likely leak after you disturb them. So either support them as-is, since they don't leak, or re-do properly.
But keep in mind, they aren't leaking, and hose clamps are fine - except that they can fail which is why they aren't used for fuel lines unless they are made correctly for that application- and can't back themselves out and loosen up easily...which can happen to normal hose clamps.
Reality- rarely happens. So throw a couple zip ties on there and go drive for the summer. If you lose oil pressure turn the car off. But you'll know because if those fail both right side tires will be covered in oil and you will be sliding off the road as you notice the oil pressure gauge at zero. Not to worry!
...and then over a winter or sometime when the car is down for work, swap them at that time.
Good question brought up. What is the pressure of the oil coming from the case through the lines. We know that the same pump pressurizes the oiling of the case to 5 bar +/- but how much pressure is sent to the filter and sump? Is the second half of the pump a different pressure? I am assuming considerably less just for sheer volume and dia of the pipe.
I had a similar fix done to my 90 C4 which is now a track car. Eventually the hose clamps failed the PO and the car made a mess. So instead of fixing it properly they just abandoned the car for 10 years. Proper clamps are critical especially for track use. I just had a problem with the plastic oil filler cap overheating expanding and coming undone on track and I will say the cost of speedy dry and the hours of cleaning I have ahead of me is a lot less than having the proper clamps in palce.
T bolts like pictured above are nicer, but the worm clamps in your pic, while not ideal, work just fine. I believe I have the same type, where the lines were replaced. I'd think there is a slight pressure drop just from the lines/cooler assembly, but it can't be that much. I never really thought about the high pressures though going through the system and if it would be an issue. I'm sure mine weeps, I am gonna look at it today. Yours looks fine and I wouldn't worry about it.
Look at all modern water cooled cars using worm clamps on heater hoses, which are also pressurized systems when hot.
Track use and street use are very different - kind of like aircraft vs car engines. A car engine fails worse case is an inconvenience and a delay. Aircraft engine failure worse case - no more aircraft. So I do see the point that you want to prep a track car differently. You may get away with a compromise for a street car - track car not so much. At least that's how I see it.
Pressure on the scavenge side should be very low unless there is a problem. First oil doesn't get sent to the front until its already hot and thin so should flow well. The only resistance is the cooler and the oil filter neither of which should have much resistance. My car has a similar repair and I have the replacement hose for years but just have not got around to replacing it.