Four Winns Temp Gauge Issue

[TexasFlyer]

I've been having an issue with my temp gauge on my 2001 Four Winns 180 Horizon 180 with the 5.0L Volvo Penta. The gauge shows almost in the red when the engine idles more than a few minutes and drops down when rpms go over about 2000. I know what you're thinking, that sounds like an overheating issue, not a gauge issue. Well, I had initially tried to troubleshoot it as such last year with the help of some good guys on here. After replacing the thermostat and impellor to no avail, I bought a pyrometer and scanned the entire engine and the highest temp on the engine I could find with the temp gauge showing almost in the red was 162 (right in the themostat range of 160). So the engine isn't overheating... I've heard of others having issues with the VDO gauge clusters that Four Winns installed in some years. Any one on here have any luck troubleshooting problems with these gauges, sending units, etc? I ran the boat last summer as it was, but if the boat ever actually does overheat, I'll think it's just the gauge and fry the motor so I'd like to have a working gauge. Any help would be greatly appreciated!

 

[GTBecker]

Re: Four Winns Temp Gauge Issue

With ignition on but engine not running, try shorting the temperature sender terminal to the block; the gauge should pin. Disconnect the sender lead; the gauge should be at zero. If so, the sender is bad. If not, the gauge (meter, actually) is likely bad.

Tom

 

[generator12]

Re: Four Winns Temp Gauge Issue

I've got a Four Winns with a temp. indicator problem also. Running around 160 degrees (infra-red gun) the gauge was barely off the lower pin. Removed and shorted the gauge wire to engine ground and the gauge pegged high.

Replaced the sending unit with one from a warehouse and now read about 210 degrees while the gun shows 160.

Summary: The gauge is an ammeter and is in series with the sending unit, which is a variable resistance. The combination is tied across the 12 volt system whenever the ignition key is "on". When the resistance of the sending unit increases (cooler temp.), the current is reduced and the gauge (ammeter) reads lower. Higher temp. results in decreased resistance and a higher current level, so the gauge indicates a temp. increase.

The key in my case (and probably yours) is to get a sending unit which has the correct resistance profile for the ammeter (temp. gauge), or vice versa. It's obvious that the combination I presently have is mis-matched.