Overheating problem on 520i E34

Hi Guys,

First post here, and i have a bit of a problem!

Last wednesday, my 1995 E34 (520i) overheated. Anyway, had it trucked back to the house, and had a quick look under the bonnet. I replaced the thermostat the following morning.

Anyway, the car starts as normal, with the viscous fan turning, it continues to warm up, and after about 10-15 minutes sitting at idle, it starts to overheat (the temp gauge goes above half). With the bonnet down, but not closed, the viscous fan doesn't begin to speed up at 3/4 on the temp gauge. The heaters in the cabin also are blowing cold (no heat, even on full hot setting).

Had a mobile mechanic look at it, and he said only some of the hoses going to the heater section (top right as you look at the car from the front), were hot, with others cold.

Anyone had this problem before? Anyone any ideas?

02:20 AM

Hello to all

A major problem with the Bmw E34/E32 especially the BMW M30 3.5l out of the 535i: overheating.Don't expect the headgasket to last long in these conditions.The temperature needle should be at the 1/2 mark all the time. If the needle is near the 3/4 mark or red area, you have an overheating problem, fix it soon.On the BMW E34 525i 92 on and the E36 325i/is with M50 engine, the engines were fitted with plastic impellers waterpumps. These waterpumps fails, the impeller desintegrates and you are left with no waterpump at all... the engine overheats. You need to check that you have a waterpump with metal impeller. Change your waterpump ASAP if yours has a plastic impeller.
Understanding the cooling system:
• The waterpump (centrifugal type) is driven by a belt. It allows the coolant to circulate.
• The thermostat controls the coolant flow into the radiator. Closed when the engine is cold (nothing goes in the radiator, open when the engine gets warm to flow the coolant inside the radiator and cool it down.
• The primary coolant fan is mounted to the front of the waterpump with the fan clutch.
• The fan clutch is a viscous fluid type that control the speed of the fan based on engine compartment.
• A two speed auxiliary cooling fan is mounted in front of the condenser. It is uses when the A/C operates and when coolant temperature exceeds 196F (91C)
• The fan shroud is also an important item not to overlook: the presence of a shroud, with about 1/2" to 3/4" clearance between the tips of the fan blades & the shroud opening, and the fan inserted about 1/2 way into the shroud opening is essential for efficient cooling performance.

Have a nice day

Used Auto Parts

	#1
prettyfrancis	Overheating problem on 520i E34 Hi Guys, First post here, and i have a bit of a problem! Last wednesday, my 1995 E34 (520i) overheated. Anyway, had it trucked back to the house, and had a quick look under the bonnet. I replaced the thermostat the following morning. Anyway, the car starts as normal, with the viscous fan turning, it continues to warm up, and after about 10-15 minutes sitting at idle, it starts to overheat (the temp gauge goes above half). With the bonnet down, but not closed, the viscous fan doesn't begin to speed up at 3/4 on the temp gauge. The heaters in the cabin also are blowing cold (no heat, even on full hot setting). Had a mobile mechanic look at it, and he said only some of the hoses going to the heater section (top right as you look at the car from the front), were hot, with others cold. Anyone had this problem before? Anyone any ideas?

	#2
charles1	Hello to all A major problem with the Bmw E34/E32 especially the BMW M30 3.5l out of the 535i: overheating.Don't expect the headgasket to last long in these conditions.The temperature needle should be at the 1/2 mark all the time. If the needle is near the 3/4 mark or red area, you have an overheating problem, fix it soon.On the BMW E34 525i 92 on and the E36 325i/is with M50 engine, the engines were fitted with plastic impellers waterpumps. These waterpumps fails, the impeller desintegrates and you are left with no waterpump at all... the engine overheats. You need to check that you have a waterpump with metal impeller. Change your waterpump ASAP if yours has a plastic impeller. Understanding the cooling system: • The waterpump (centrifugal type) is driven by a belt. It allows the coolant to circulate. • The thermostat controls the coolant flow into the radiator. Closed when the engine is cold (nothing goes in the radiator, open when the engine gets warm to flow the coolant inside the radiator and cool it down. • The primary coolant fan is mounted to the front of the waterpump with the fan clutch. • The fan clutch is a viscous fluid type that control the speed of the fan based on engine compartment. • A two speed auxiliary cooling fan is mounted in front of the condenser. It is uses when the A/C operates and when coolant temperature exceeds 196F (91C) • The fan shroud is also an important item not to overlook: the presence of a shroud, with about 1/2" to 3/4" clearance between the tips of the fan blades & the shroud opening, and the fan inserted about 1/2 way into the shroud opening is essential for efficient cooling performance. Have a nice day Used Auto Parts Last edited by charles1 : 01-12-2010 at 02:20 AM.