'94 Volvo Penta 5.7 GiPMDA. Thermostat is 160*, temp gauge rises normally to 190*, and sits there all day long, but highest IR temp anywhere on the engine is 145*. This model never had a warning horn, though it will go into limp mode (electrical problem affecting TBI). Since this vintage has VDO gauges, I'm told by VDO (and other sources) it should have a VDO sensor, gave me the item number of what they said I needed (single wire spade connector). The big question, where is the temp sender? There is a two-wire sender at the thermostat housing, disconnecting it does nothing to the gauge. There is a one-wire sender in the lower starboard -side block, aft, pretty sure it's in a water jacket. Disconnecting it does nothing to the gauge, and it's a protected center electrode plug. No, it's not in a riser, manifold, or in the rear of either head. Anyone know for sure where to find this sucker ...
'94 Volvo Penta 5.7 GiPMDA..... looks as though you have the AQ series drive..... of which is great!
Here's the Closed Cooling System GI PMDA version.
All of these numbers are SEQ numbers (sequence part numbers) and will correspond to the OEM part number in the list.
Where you see the SEQ #18, the locating line passes through what may be the temp sender.
For some reason this schematic does not asign an SEQ # to this part!
OK, there is a two-wire sensor at that location at the thermostat base. The next question, what should happen to the gauge if this sensor is disconnected before or during operation? I disconnected this sensor after running up to op temp, and it didn't affect the gauge. The other single-wire I referenced is and oil pressure switch sensor. Thanx ...
On the intake is where it is - buried under 3 water hoses. Couldn't even reach it with a finger, followed a single grimy wire from a mini-harness. Got the middle hose off (finally) and there she was. 3/4 deep well accessed perfectly and it came out easily. The replacement by VDO has a single spade connector, the one I took out had a bent over connector. Got the sender installed, bent the connector over (no way the hose goes on if it's vertical), got the wire connected (finally), got the hose hooked back up. Fired her up ... and the temp gauge was doing nothing. Checked the wire, it had disconnected while putting the hose back. Finally, fired her back up and the gauge worked as advertised, took about 15 min, but the gauge settled at 160*, which is the thermostat installed
