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hose replacement

mhfd112 on Wed June 12, 2013 12:55 PM User is offline

Year: 1998
Make: Dodge
Model: Durango
Engine Size: 5.9
Ambient Temp: 83
Pressure Low: 28
Pressure High: 170

I put a hose assembly on my brother in law's Durango. It was working and cooling well after topping off, but after adding dye we found the hoses to be leaking. After the hoses were replacec, we vacuumed and recharged. Worked good. Vent temps in low 40s. While driving it home he heard what he described as a growling noise. Heard it three times. Yesterday the ac wouldn't work. I looked this morning at it and there was dye in the area of the pressure relief on the back of the compressor.

I noticed this morning on the muffler 8oz was wrote on the side of the muffler. This was a new hose. I was wondering if there was a big dose of oil in the hose? If so, could this cause the pressure relive to open?

iceman2555 on Wed June 12, 2013 5:10 PM User is offlineView users profile

It is highly unlikely the cause of the pressure relief valve is due to the hose replacement. Never encountered a hose assembly that was shipped with lubricant. The concern would be possible debris within the condenser. When a system looses refrigerant via a leak the system lubricant movement is effected. A undercharge will reduce the amount of lubricant in the compressor and the result is production of debris. Was the system serviced prior to the hose change, has it been 'topped off' on other occasions? If so there is a good probability of internal compressor damage. There is no statement of how the system was recharged, gauges and cans or with a recharge machine. Lack of proper recharge can also result in compressor damage.
The 'growling' noise is a bit disconcerting and typically indicates a possible internal compressor problem.
A simple test would be to measure the temp of the discharge line. If the temperature is hot to touch and the temperature increases with run time, this would be a good indication of a condenser restriction.
However, this test requires that the system be properly recharged. Try operating the engine at idle for 5-7 minutes test the discharge line temp. Increase RPM and re test line temp, should the line temp increase drastically, once more a possible condenser flow concern. Should this be the problem, then extensive repairs would be necessary, including condenser replacement.
Another cause of PRV release could be a simple engine cooling system problem. Check the fan clutch or other engine cooling system components to determine if there is a problem.
Basically, PRV release is due to engine cooling issues or a condenser restriction. Of course, a serious over charge of the system will also cause this problem, however, it is doubtful that this is the cause.
Good luck

The strongest reason for the people to retain the right to keep and bear arms is, as a last resort, to protect themselves against tyranny in government.
Thomas Jefferson

mhfd112 on Wed June 12, 2013 5:26 PM User is offline

Late last summer it wasn't cooling very well. I found a leaky spring lock connection. I replaced o rings, vacuumed and recharged with a 30lb tank, gauges, and scale. This was the first time the ac has been touched. He bought it new in 98. He brought it back again this year. Was still cooling but not well. Added dye and found the leaky hose.

Thanks for the fast response.

GM Tech on Wed June 12, 2013 11:08 PM User is offline

If the hose assembly is on the discharge side-- then yes there is a possibility the slug that was punched out when the muffler was assemble to the line is sdtill in the muffler- and it is rattling around and plugging the muffler outlet-- I've seen it twice in my life on OEM units-- The hose manufacturer has to assure the slugs are are accounted for when punching holes in mufflers to assemble the ajoining pipes. A loose slug causes intermittent refrigerant flow stoppage and then backs up into compressor and blows the pressure relief valve. The way to determine if you have a loose slug is to remove hose and shake it-- do you hear a rattle?

The number one A/C diagnostic tool there is- is to know how much refrigerant is in the system- this can only be done by recovering and weighing the refrigerant!!
Just a thought.... 65% of A/C failures in my 3200 car diagnostic database (GM vehicles) are due to loss of refrigerant due to a leak......

mhfd112 on Sat June 15, 2013 6:10 PM User is offline

I got it going again. Problem was an acute case of cranial rectumitis. Pretty sure I had it over charged.

Learn something every time I come to this forum. From now on I will always check hoses with mufflers for rattles.

iceman2555 on Sat June 15, 2013 10:40 PM User is offlineView users profile

This seems to contradict your posted high side pressures of 170 psi. 170 psi does not reflect a seriously overcharged system. The PRV release point is approximated 425 psi.
This misunderstanding seriously supports the notion that system should be charged with the correct amount of refrigerant utilizing the correct equipment.
Did you diagnosis a 'rattle' in the muffler canister?

The strongest reason for the people to retain the right to keep and bear arms is, as a last resort, to protect themselves against tyranny in government.
Thomas Jefferson

mhfd112 on Tue June 18, 2013 3:41 PM User is offline

I didn't find anything in the hose.

He stopped by Sunday and it is still working good.

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