engine running cold

[danny2010]

all weekend my engine wont get up to the center of the temp gauge. it usually stays on 1/4. is this a major problem? or is it just because its been below freezing everytime i drive it.

is it a good idea to drive it back to ohio this morning? its roughly a 3 to 3 and a half hour drive. i just dont wanna do harm to it if this is gonna mess it up

[davloh]

My 633 has always seemed to run on the cool side first quarter of the temp gauge. I recently replaced the thermostat and same result. My manual says it is normal to run anywhere in the mid section of the gauge in other words not in the red or blue. I have not had any issues but will be curious to hear from the experts.

[danny2010]

Well that puts me at ease some. It seems like it just started doing it when I replaced my battery though is the weird thing

[86GT635]

It's kind of hard to say. The coolant temp sensor lets the ecu know how much fuel to send.

You should fix the problem. The temp guage should be at 12 o'clock during full operating temp. I wasn't using a fan shroud at one point in the winter and it made the engine run a bit colder than normal. A fan clutch that is always pulling strong will pull too much air. The thing about running a engine colder than normal is that it uses more fuel and makes the stoich rich.

You might get on the highway and it warms up, and I would probably wing it myself, but it could do some damage. Maybe a clogged cat, fouled spark plugs, excessive soot on the valves.

[Mike Goble]

I had a too-cool problem with my Bavaria and a new thermostat fixed the problem. I put both thermostats into a pan of water and the old one opened 20 degrees before the stated opening value, and the new one opened at the right temperature. I also installed a temperature gauge so I wouldn't have to rely on a dimensionless meter.

[Shipper]

there are 7 lines on my 633's temp guage. Even at 30 degrees C it runs on the first of the seven lines. On the race track after 15 or so hot 6250 rpm laps it will climb to the 5th line, and that is on a hot hot day. These cars run cool. They have big radiators for their engine size. Never seen one run with the temp needle on half, always below.

I agree with Mike though. Put a new, higher temp opening thermostat in if you want the car to run hotter.

[euroshark]

My 5 runs around 1/5 to 1/4 on the gauge so I like to block half of the radiator with cardboard during the winter. I also run it without the mechanical fan except for in the summer months.

[Mister6er]

My 5 runs around 1/5 to 1/4 on the gauge so I like to block half of the radiator with cardboard during the winter. I also run it without the mechanical fan except for in the summer months.

My 1981 runs about a 1/4 tops. I also run mine without the fan clutch since it exploded and slashed my previous radiator.

[Rallim]

E12 and E28 temp gauges are way different. As far as I can tell E12 gauges read alot lower, whereas the E28 gauges read somewhere between 1/3 and 5/8ths

[davloh]

My 1981 runs about a 1/4 tops. I also run mine without the fan clutch since it exploded and slashed my previous radiator.

you guys don't have a problem with overheating? Has anyone converted to all electric fans and eliminated the fan and clutch for year round use? I know that was a good upgrade on my old TR6.

[Mike Goble]

On my 72 Bavaria I removed the mechanical fan and put the auxiliary electric fan from a 90's 525 in front of the radiator, and it works very well. I used the 91°/99° switch and a Volvo 2-speed fan control relay to run it, but it almost never comes on. Even in the 100° summer heat I have to let it idle in traffic for 10 minutes to get low speed to engage. As soon as the low speed engages, the temperature goes down and the fan shuts off.

[todor]

Did anyone ever figure this out? I just rebuilt the engine on a '78 Euro 635csi (and put in a new thermostat and water pump) and now it runs pretty low on the temp gauge. I don't know how it ran before the rebuild - I bought the car with a blown head gasket.

Is this normal or do I need to do something about it? I'm worried to rev the engine high when the temp is so low... Or could it be that the sensor is wrong?

Here's what I get (note: this is a Euro cluster; and yes, I was driving when I took this pic)

[Bentsdl]

My car (also a early model) runs at about the same temperature (position of the needle). I also feared that it might run cold, I measured the actual temperature of the coolant with a digital thermometer and it was actually around 80-85C. So I don't think it's really something to worry about.

You can check the functioning of the thermostat (somewhat) by checking if the radiator heats up moments after you turn on the engine. If it's functioning properly that should take a couple minutes, after the thermostat opens.

[gilach]

I have a 1981 Euro 633csi modified with cam and headers, my temperature gauage is exactly ash shown below in your pix. when warmed up.

Did anyone ever figure this out? I just rebuilt the engine on a '78 Euro 635csi (and put in a new thermostat and water pump) and now it runs pretty low on the temp gauge. I don't know how it ran before the rebuild - I bought the car with a blown head gasket.

Is this normal or do I need to do something about it? I'm worried to rev the engine high when the temp is so low... Or could it be that the sensor is wrong?

Here's what I get (note: this is a Euro cluster; and yes, I was driving when I took this pic)

[1986series6]

I would not go by any gauge, to know exactly the temp-I would use an infrared.

https://www.amazon.com/Infrared-Ther...33104962&psc=1

[tschultz]

Horizontal on the early gauge is correct.