Engine Temp - Diesel

[bunglefuzz2]

2005 Mondeo Diesel 130

What temp should the engine be running? I'm sure last winter the heater blew lovely and warm with bags of red hot air if necessary. Recently the heater can only be described as just about sufficient. Also, the temp gauge is usually pointing to 60, or 70, unless in traffic when it may pop 80 until I get going again. I thought it would be the thermostat stuck open, but I've had a new one fitted and it's still doing it.

Please help. Shouldn't the temp gauge point somewhere in the middle and remain fairly constant in the middle as the thermostat opens and closes in response to varying driving conditions?

Could it be something other than the thermostat?

It's quite mild weather at the moment, surely the heater should blow hot?

It just seems so unlikely to be a clogged heater matrix and the temp gauge, but then also unlikely to be a faulty new thermostat.

Many thanks.

[pragmatix]

There is an oil thermostat too it could be that that stuck

[boylin]

ᴍʏ 2.0 ᴅɪᴇsᴇʟ ᴀʟᴡᴀʏs ᴡᴀʀᴍs ᴜᴘ ᴛᴏ ᴀʙᴏᴜᴛ 74'ᴄ ɪɴ ᴛʜᴇsᴇ ᴛᴇᴍᴘᴇʀᴀᴛᴜʀᴇs ᴏғ ~5'ᴄ ᴏᴜᴛsɪᴅᴇ, ɪɴ ᴛʀᴀғғɪᴄ ɪᴛ ᴡɪʟʟ ʀᴇᴀᴄʜ ʙᴇᴛᴡᴇᴇɴ 75-90'ᴄ. ɪᴛ ʜᴀs ʜɪᴛ 90-100'ᴄ ʙᴜᴛ ɪᴛ's ɴᴇᴠᴇʀ ɢᴏɴᴇ ᴏᴠᴇʀ 100'ᴄ.