Ironflight

Ironflight

VAF Moderator / Line Boy
Mentor
I'm curious about something that I have never seen discussed around here - the gains to be had by flushing an oil cooler. One of our airplanes is closing in on 1900 hours on the oil cooler, and while it might just be the insanely high ambient temps we are having this summer, the oil is running a bit warmer than usual - could it be we might want to flush the cooler to see if there is an improvement?

I talked with a fellow at Oshkosh from Pacific Coolers, and he said that they advise a flush every 500 hours. Of course, he was selling flushes....so I am interested if anyone here has had theirs flushed, and if so, did you notice an improvement in oil temps? I've put thousands of hours on oil coolers in my planes over the years - never had one serviced.

Paul
 
Flushed & soaked

Flushed 6 times with fuel to rinse oil out then soaked for an hour with carburetor cleaner from Solder Seal. No change in oil temps. My oil temps have gone from 185 on hot days to 190 over a period of 7 years and 1400 hours. Cooler is on the firewall fed with 3 inch hose. The 1st 3 years I had half of the hose inlet blocked on the #4 cyl baffle to get up to 180 on a normal day. Had to remove the inlet block in year 4. When I rinsed and soaked the cooler I did not see any crud come out. 0 360 Lyc 180 hp. 6A cruises at 165-170 knots at 6500 PA (8500 DA) oat 65 f. I also had to redo the top cowl about year 4 to correct a poor match with the spinner; the inlets were reduced in height about a half inch. Would have kept them the original height based on postings I have read on this forum since then. So I did not see evidence the inside of cooler needed service. CHTs at above cruise were 373, 367, 365, 359 in numeric cyl order. Dale
 
I sent my cooler to Pacific in an attempt to resolve oil temp issues I've experienced this summer. They did a very nice job, an overhaul actually, for about 2/3 the price of a new Niagara cooler from Vans. No noticeable difference in oil temps afterward however.

On the other hand the local FBO sent an oil cooler from a Saratoga to Pacific and flushing did help in that case.
 
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Funny that you bring this up. We just pulled a 3000 hour o-235 off a 152. We had an oil cooler on the shelf that had come back from "overhaul" and I looked at it and felt it was unserviceable. (looked like all the overhaul amounted to was a overdone sandblast). The 3000 hour oil cooler was new when it was installed and looked in good shape other than dirty. We soaked it in avgas for a couple of hours and ran some solvent through it and concluded that it nothing came out of it. We change the oil religiously at 50 hours and I suspect if that has been your experience, you will find the same.

On a side note, another "overhauled" oil cooler on a 172 sprang a leak recently after about 2 hours in service. IMO, if the oil cooler looks ratty, buy a new one and not overhaul it.
 
Paul,
I have no personal experience but John Schwaner in his Sky Ranch Eng. Manual (page 337) certainly recommends this for high time engines.
I also wonder if hoses can deteriorate to an extent that the flow can be impeded given the very high flow rate (~10 gpm). This would be an easy check.
Doug Gray
 
When I did an overhaul on my Grumman AA5 last year I sent the oil cooler to Pacific for flushing and test. Came back with a Red Tag on it. They said the varnish was all that had kept it from leaking:eek:

About 1850 hours on the engine since last overhaul, no sign in the logs of removing the cooler since it was installed. I think regular flushing and test would be very advisable. I plan to do it.

Stan

N67SL (reserved)
RV7A (fuse)
KCCB

N6085L
73 Grumman AA5
KCCB
 
On certified planes I've sent quite a few out for a flush/inspect (usually at overhaul) and sometimes they have a lot of junk in them. Of course, these planes all average like 40 years old now & many have been rudely treated. I supect the average RV would fare better as they generally aren't running some kinda unknown stew for oil.
 
Ironflight said:
I'm curious about something that I have never seen discussed around here - the gains to be had by flushing an oil cooler. One of our airplanes is closing in on 1900 hours on the oil cooler, and while it might just be the insanely high ambient temps we are having this summer, the oil is running a bit warmer than usual - could it be we might want to flush the cooler to see if there is an improvement?

I talked with a fellow at Oshkosh from Pacific Coolers, and he said that they advise a flush every 500 hours. Of course, he was selling flushes....so I am interested if anyone here has had theirs flushed, and if so, did you notice an improvement in oil temps? I've put thousands of hours on oil coolers in my planes over the years - never had one serviced.

Paul
Click to expand...

Paul,

Did you ever find a solution to your oil temps running a bit warmer than usual? Did you get the flush done and if, did it help?

I'm experiencing higher than normal oil temps my RV-8 equipped with a Titan (ECI) IO-360. Wondering if the flush is worth trying?
 
Paul,

I think I found you're probable answer to my question in this post from a different thread.

I will call Pacific Coolers.

Thank you,

Charlie

Ironflight
11-20-2012, 08:47 AM
I ran the first Niagara for almost 1500 hours on the RV-8 without problem - then the ears cracked - the only damage in all that time. Pacific Coolers had refurbished Niagaras for something like $200 and based on the service I got from the first one, I just went with that again.

Paul
 
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