Oil Consumption and AC Use (1 Viewer)

[infinitesteps]

I have only had my 80 since the spring so I am still getting to know her. This summer I attempted to fix the AC (recharged). It blew cold for a brief time but doesn't currently work.

What is weird is that when I use the AC I seem to consume more oil. During July I was using almost 1 qt per 100 miles. I gave up for now on the AC and fixed my automatic windows instead. As a result I haven't been using the AC (or the fan) at all and now my oil consumption seems more normal - at 500 miles since I topped it off I am currently 60% on the dipstick range.

Is this an imaginary correlation? Is it possible for (malfunctioning) AC use to cause oil consumption?

A few other possibly irrelevant facts:

- When I ran the AC, it didn't really work so I didn't run it for very long but I did try repeatedly
- The oil light came on in the same trips as the AC use (I am pretty sure) -- light was correct the oil was actually low
- I have no visible drips under the truck but it does smoke on start up
- There is almost always a faint odor (burning oil I think) but when I run the AC it seems to be a more potent odor
- At the beginning of the summer I used a fuel additive in two consecutive tanks (Sea Foam 16 Ounce Fuel Additive I think)
- The rear heater was bypassed last spring by the PO due to rusty line coolant leak

 

[flintknapper]

Aside from the increase in engine load that the A/C causes (approx. 5-8 hp.) there is no direct correlation between A/C use and engine oil consumption. They are separate components and circuits.

Oil leakage/consumption of 1 qt. per 100 miles is extreme and points to a need for repairs...I am sure you know.

'Smoke at start up' is oil getting past the valve guide seals (at best). You could also have worn valve guides.

 

[ZackR]

I'd back burner the AC for now and focus on the oil leak (unrelated as @flintknapper pointed out).

You say no drips but using a quart per 100 miles?? These 80 series cruisers are known to leak oil so I'd be surprised there are no external leaks. If you haven't already I'd clean the engine and confirm there are no external leaks.

 

[inkpot]

Your either smokin or drippin if yur loosin a qt per 100 miles!
Maybe someone put a 2-strike motor in.it?

 

[Michael Hanson]

Hi, I'd look for leaks underneath and do A compression test and leak down test. Mike

 

[Red Merle]

Probably valve stem seals. Just do the whole head gasket job.