2009 Merc 4.3L TKS Temp Gauge Issue

[mschmidt33]

All of a sudden the gauge does not work. It stays buried full cold. I'm thinking either a stuck open t-stat or a bad sender. I pulled the sensor wire and grounded it out and the gauge buried itself on the hot side. Next steps to determine which part to replace?

Pull sender and check in hot water with multimeter? What resistances should I be looking for?

Pull t-stat? Figured if I go this far I should have a gasket and new t-stat on hand, thoughts?

Mike

 

[Bondo]

Re: 2009 Merc 4.3L TKS Temp Gauge Issue

I pulled the sensor wire and grounded it out and the gauge buried itself on the hot side.

Ayuh,... Either the sender is junk, or it lost it's ground...

 

[Don S]

Re: 2009 Merc 4.3L TKS Temp Gauge Issue

Is the engine warming up at all? Might check it with an IR Temp gun right next to the sender.

 

[mschmidt33]

Re: 2009 Merc 4.3L TKS Temp Gauge Issue

Is the engine warming up at all? Might check it with an IR Temp gun right next to the sender.

I idled it on the muffs for 10 min and the manifolds got hot but the tstat housing was sweating and cold to touch. Guessing IR gun would show cold. Pull tstat? Drop in boiling water?

 

[Bondo]

Re: 2009 Merc 4.3L TKS Temp Gauge Issue

I idled it on the muffs for 10 min and the manifolds got hot but the tstat housing was sweating and cold to touch. Guessing IR gun would show cold. Pull tstat? Drop in boiling water?

Ayuh,... The T-stat housing handles all the cold water comin' in,...

If ya wanta check if the T-stat is workin',...
Ya gotta check the temp of the intake manifold, Under the T-stat housing...

 

[mschmidt33]

Re: 2009 Merc 4.3L TKS Temp Gauge Issue

Ayuh,... The T-stat housing handles all the cold water comin' in,...

If ya wanta check if the T-stat is workin',...
Ya gotta check the temp of the intake manifold, Under the T-stat housing...

OK, so if IM is hot the t-stat is working?

 

[Don S]

Re: 2009 Merc 4.3L TKS Temp Gauge Issue

OK, so if IM is hot the t-stat is working?

Basically yes. The engine should warm up to 160? before the thermostat starts to open. If it doesn't get that hot, the thermostat is probably suck open and the engine won't warm up unless under load (On plane)

 

[mschmidt33]

Re: 2009 Merc 4.3L TKS Temp Gauge Issue

Basically yes. The engine should warm up to 160? before the thermostat starts to open. If it doesn't get that hot, the thermostat is probably suck open and the engine won't warm up unless under load (On plane)

I was pulling the kids for a half an hour on the tube and the gauge never moved so I'm guessing it's the sender. Just ordered a sender and the tstat, gaskets just in case. Any tips for the swap? thanks for all your help guys much appreciated

 

[Bondo]

Re: 2009 Merc 4.3L TKS Temp Gauge Issue

I was pulling the kids for a half an hour on the tube and the gauge never moved so I'm guessing it's the sender. Just ordered a sender and the tstat, gaskets just in case. Any tips for the swap? thanks for all your help guys much appreciated

Ayuh,... The gasket with the rivets, goes 'tween the housing, 'n the motor...

 

[mschmidt33]

Re: 2009 Merc 4.3L TKS Temp Gauge Issue

Ok ran it WOT for 5 min today and got the temp to come up a bit. So sender is good. Just need to replace tstat and gasket I assume