Just bought a 2004 325xi, question about temperature gauge

**e46mayn** · 06-15-2019, 02:09 AM

Like the title says, I bought a 2004 325xi, super clean, 1 owner, 80k miles today. It drives great and seems to work great except for the common window issues and a few headlights that are out (didn't know xenon headlights were so expensive, damn). But after driving about 40 miles home from the city I bought it in, and "testing the power" around town for a little bit, when I got home and was letting it idle, the temperature gauge starting going past the middle and went to the second line on the right, then got right before the red part of the cluster. It never went past that point right before the red, but it has me worried. Owner claims it has a new water pump and fan. Manual says that it's normal for the gauge to get to the point right before the red but if it gets to the red part then have it looked at.

One thing I noticed when looking it over was that while idling, a kind of small squeaky noise comes from the belt right in the front of the hood where the grill is. I didn't worry too much about that because the car was so clean and seemed like a steal. Best one I've come across in over two months of searching. But yeah, now I'm worried. I knew what I was getting into getting an older BMW with 80k miles, but yeah, was hoping not to have to do any repairs right away lol.

I guess my question is.. is it normal and ok for the gauge to get near the red but not go into the red? And if it is a problem, what are some probable causes based on that squeaky noise which is the only thing "off" about the car? I didn't notice any coolant leaks. I haven't really done much work on cars besides replacing a radiator and thermostat on a honda civic and basic oil changes, but if I could figure out what is causing the problem or how to diagnose it, I could probably fix it myself with the help of youtube.

BTW, some more info, the temperature gauge only goes up when idling. If i accelerate pretty fast after idling at a light then the gauge drops right back to the middle. Also, even when idling, if it does go up near the red, it kind of goes up and down, doesn't just stay in one spot. This has me thinking it's the thermostat but like I said I'm no mechanic.

**mistreku** · 06-15-2019, 04:51 AM

I'd say that's not normal, it should stay bang on the middle. From what you're describing it seems to be a problem with the radiator fan. When idling and seeing the temp gauge creep up, is the fan working? It sounds as if the radiator doesn't get enough air flowing through (fan's job) and it will only cool down when driving. Check fuses and fan's connector.

**mistreku** · 06-15-2019, 05:00 AM

Could also be the thermostat, not opening enough maybe, but you're saying the temp drops fast after driving away, so I'm more inclined towards the fan being the culprit.

**MarcoZandrini** · 06-15-2019, 07:53 AM

The consensus here and on other bimmer forums is that the E46 cooling system needs to be overhauled at 100k miles. That includes replacing:
- water pump (Saleri or Graf)
- thermostat (Whaler)
- upper and lower radiator hoses (Conti)
- expansion tank (Modine ONLY)
- expansion tank cap (Modine)
- serpentine belt (Conti)
- tensioner and idler pulleys (INA)
- radiator (Nissens or Behr) (optional)
- engine block coolant drain crush washer
- BMW coolant
- distilled water
- fan clutch (Sachs) (auto transmission only).

Your engine is overheating. Do not allow the temperature gauge to get passed the 3/4 mark or else you’ll have an expensive paperweight - an overheated bmw engine. What’s happening now is the fan clutch is failing. This clutch sits on the water pump shaft and has the fan attached to it. It’s a viscous clutch in that the speed of the fan increasingly matches the engine’s speed as the underhood temperature increases. It needs to be replaced ASAP as the fan isn’t spinning fast enough to keep the engine cool.

Tge installation of aftermarket cooling system parts is strictly verboten. Do not ever install cooling system parts from a parts store like auto zone or oreillys.

The first step is to get the part numbers for the parts. Go to www.realoem.com and enter the last 7 characters of the car’s vehicle identification number. Hit enter and bookmark the page. Cooling system parts are located in the engine and the radiator sections. Next, go to FCPEuro to buy the parts. Now, for each part number you enter FCPEuro will show 4 different parts:
- BMW branded (expensive)
- original equipment (same as BMW branded but much cheaper; these are known as “original equipment” (OE) parts)
- original equipment manufacturer (part made by a supplier to BMW, but not the supplier of this part; known as “original equipment manufacturer (OEM) parts)
- aftermarket.

Buy either OE or OEM parts.

Off my soapbox.

**mistreku** · 06-15-2019, 07:58 AM

^what he said, with a small addition. if you have viscous fan, why not go for an electric one, not hard to retrofit and it frees a couple of ponies.

**Critter7r** · 06-15-2019, 09:05 AM

I'd guess you've got the double whammy of electric fan and fan clutch failure. neither is cheap, but the clutch is probably the easier repair. Fix that and you'll be able to keep driving it without an operational electric fan (ask me how I know), although your A/C won't work without that electric fan working.

If the electric fan IS working, then you likely have a failed fan clutch and a radiator that filled with road debris. In which case, you'd take off the fan shroud when you replace the fan clutch, and while the fan is off the car, give a powerful spray of water to the radiator, spraying from inside the engine compartment toward the front of the car to push all the gunk back out the way it came in.

**jclausen** · 06-15-2019, 09:11 AM

The original fan clutch system works fine, personally if it needs the fan clutch than just replace it. But stop overheating the engine besides running out of engine oil it's the worst thing to play with

**e46mayn** · 06-16-2019, 01:53 AM

Just got around to checking all the replies. Thanks everyone for helping me out, much appreciated! I had my dad look at it and he agrees it’s most likely the fan clutch. I’ll order one ASAP and replace it.