Engine Size: 4.6L
Refrigerant Type: 134
Ambient Temp: 89
Pressure Low: n/a
Pressure High: n/a
Country of Origin: United States
I'm working on a friends F150. Replaced the hose assy. Attempted to pull vacuum. Pulled vac to 10-15in then stops. Checked for leaks. Checked every connection. Found a leak and repaired. Pulled vacuum, still only to 10-15in. System will not hold vacuum for more than 1 min. Switched to pressure with nitrogen expecting to find a major leak somewhere. WRONG!!! System holds 120 psi of N2. What? Will be taking truck to different shop tomorrow to rule out any equipment issues. Any other ideas?
Could be the shaft seal is pulling inward and leaking. They're designed to hold pressure, but should hold vacuum too. Any oil residue around the compressor clutch?
the truck has well over 200k miles. unfortunately, there's engine oil leaks pretty much everywhere, including all over the compressor. Was cooling fine, with minimal leakage, till discharge side of hose assy. busted just behind a crimp. I am somewhat hoping for another problem, but for by friends sake, not a compressor job. As I said, the truck has well over 200k miles; not sure how much longer it'll be running. I'm not too keen on using salvage compressors, but considering the mileage and likelihood of future engine failure, I'd hate for him to spend a few hundred dollars more in a compressor job, then a few years from now, the engine fails.
You don't need to replace the whole compressor if indeed the shaft seal is bad - just the shaft seal.
Doubt that 4.6 will fail but I see your point. On a preferably warm or hot dry day, vacuum the system down for a looooong time with engine running (A/C off of course) and hood lowered to keep the system hot. Between the vacuum and underhood temperature, that should boil off any moisture. When done, immediately charge the system before it loses vacuum.
Once the system is charged. You can place a shower cap or plastic bag over the compressor hub, let the vehicle sit overnight, and insert the leak detector probe in there. If the leak detector goes bonkers, that's where the leak is. But you never know, the system might be perfectly tight under pressure.
That shaft seal can wear a groove in the compressor shaft. If that happens, no choice but to replace the compressor.
We've updated our forums!
Click here to visit the new forum
Copyright © 2016 Arizona Mobile Air Inc.