The International Cessna 170 Association

We've had a prolonged cold spell so last Saturday I went to the airport early and plugged in my Reiff preheat system planning to make a few touch and goes later in the day. I left and returned four hours later to find my engine as cold as I had left it. I checked to insure that I have power at the end of the extension cord which I used to plug into the system. It was just too darn cold to spend much time troubleshooting it but I took a quick glance inside the cowling and don't see anything obviously wrong.

I checked the Reiff website and was reminded that the oil pan heat pad has a thermostat but the cylinder bands do not. I don't see a fuse in the system anywhere but, again, only took a cursory look. The system is about 6 or 7 years old.

Has anyone else had an issue like this? Ideas? Would a failure of the thermostat to the oil pan heat pad affect the whole system? Is there a fuse in the line somewhere that I just don't see?

We are supposed to have a bit warmer weather on Thursday so I hope to get out and pull the cowling off for more troubleshooting. Hoping someone can point me in the right direction.

Thanks!
Keith

Can you use a sharp-pointed probe of a VOM and check for voltage at the heater-end of the power cable by penetrating the power-cord? Sometimes 120 volt plugs are intermittent. The extension cord you are using might be the actual problem also.

Thanks for the suggestions George.

Yes, a volt meter will be my first check. Since no part of the system appeared to work perhaps it's the main plug... I'll narrow it down with a meter.

The extension cord is the same one I usually use. I checked it with a test light but didn't check the voltage.

Keith-
I used the Reiff system for 10 years on my C-185 in Alaska so it was used a lot, never had any problems with it.

Sounds like an extension cord or 110v supply problem of some sort to me, the pan heater is independent of the cylinder base bands.

The oil pan heater has a thermostat so it doesn’t coke the oil. Not an issue with the cylinder bands.

Good luck and let us know what you find.

Could you post a pic of the installation in your 170? It has 6 bands and a pan heater is that it?

Yes. It has 6 bands and a pan heater. I'll post a picture when I get back to the hangar on Thursday. It has a main power cord that appears to branch off with a connector leading to each component. The first branch goes off to the pan heater. Somewhere in that branch is a thermostat. Further down the line it branches off to each cylinder band, which appear to be nothing more than big hose clamps.

This is just to bring up an irritating thought: Does a sump/pan heating pad glued to the bottom... increase oil temps on hot days by insulating the sump from being as capable of dissipating heat?

gahorn wrote:This is just to bring up an irritating thought: Does a sump/pan heating pad glued to the bottom... increase oil temps on hot days by insulating the sump from being as capable of dissipating heat?

I've never considered that as I've never had a problem with excessive oil temps. My oil temp runs about 180 in the summer with the sump winterization plate removed. Maybe a little warmer on a hot day but I've never seen over 200.

gahorn wrote:This is just to bring up an irritating thought: Does a sump/pan heating pad glued to the bottom... increase oil temps on hot days by insulating the sump from being as capable of dissipating heat?

NOT IN ALASKA! Been doing it for years on many different Aircraft.

Not on my LYCOMING!

I think I found my problem. The following picture is from the bottom looking up at the firewall. The blue cord was added to extend the power cord down to the lower edge of the firewall for easy access. Apparently the connection between the blue extension and the Reiff power cord wasn't good. I wiggled it a bit and it started working. I suspect perhaps some corrosion on the connection there. It is safety wired together so I didn't take the time today to undo it and clean the connections properly but I will when I get a chance.
As to the question about the oil pan pad insulating the pan, I didn't remember how small the pads are. There are two, one on each side of the pan. They measure 1.5 inches by 4 inches. They also appear to be made of some metallic material, perhaps soft aluminum?, so may dissipate heat very well anyway. Here's a pic of the left side of the oil pan showing the heating pad.
Here is a picture of the top of the engine, showing how each cylinder heat band is branched off of the main power supply.

I was thinking not about the Reiff system but another which uses a larger, rubber heating pad. (At least that's what was shown in the advert.)
Thanks for the pics.

If we look at “The 170 News “ first quarter 2002 page 11 has a very good and cheap engine heater .