what is the probable cause of bmw 5 series cars (old models)overheating and how much to fix??

Question

i am thinking of buying one with this problem ,car is perfect otherwise

Answer 1

You have to consider a few things.

Firstly, engine damage:
If the engine has overheated many times over, head gasket, pistons, seals...etc could be already damaged. You probably need a complete engine overhaul to fix these.

Secondly, cause of the overheating:
This is actually an easier fix compared to the first one.
They key is to be able to pinpoint what the cause is:
- Water pump with shattered impeller (need to clean out the whole system)
- Leak in the system
- Faulty Fan
- Bad/wrong coolant
- Bad/worn hoses
- Bad thermostat
- Clogged system

It's really a lot of work and it's definitely not recommended that you buy such a car... unless you really like the car so much that time and money isn't an object to you.

Answer 2

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Located deep inside of this BMW N62 engine is a Coolant Transfer Pipe, which carries antifreeze from the Water Pump to cooling chambers within the engine. However, the Front Seal on this Cooling Tube can fail in as little as 40,000 miles, and start leaking antifreeze from the engine block, through a weep hole in the Timing Chain Cover. When this happens, the car will lose antifreeze from the engine, and the engine will overheat.


In the past, this has been a very expensive repair because it required disassembly of the engine, in order to access the leaking Cooling Pipe Seal. The original method of replacing the crossover Coolant Transfer Pipe required the removal of the Timing Chain Cover. This repair could cost $6,000 or more at the BMW Dealer.


Then, an after-market Collapsible Coolant Pipe was developed to save time and money on this repair. This Collapsible Coolant Pipe method involves removing the Intake Manifold, cutting out the old Coolant Pipe and installing the after-market Collapsible Coolant Pipe. But even this method required many hours of shop labor and expensive parts and supplies. The repair bill for this method can still cost between $1,500.00 and $2,500.00 to remove the Intake Manifold, cut out the old Coolant Pipe and install the new Collapsible Coolant Pipe.


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Answer 3

Somehow you should examine the water pump impeller. There were a few years when water pump impellers were made of plastic which, with high mileage could become broken off. The five series waterpumps have been around for years. Try to find a new water pump with a steel, brass, or cast iron impeller. When installing a new water pump, make sure that the "V" belts are properly snug. Do not overtighten, but make sure that the impeller is turning with the speed of the engine. A binding water pump impeller may wobble when the belt is too tight or when the water pump is worn out. There are no bearings in a BMW water pump.

Answer 4

1. Coolant either needs to have the air bled out of it.
2. There was a leak somewhere and some idiot put stop leak in it instead of replacing the radiator and now the line is clogged.
3. It needs a new thermostat.
4. Thermostat housing could be cracked... ( http://foreignaffairs.us/gallery/albums/userpics/10001/DSCF0006~0.jpg )

You shouldn't drive it if it is overheating though. Excess heat will cause the pistons to expand and ruin the metal sleeves that separate the piston from the engine wall. If these are destroyed you will pretty much need a new engine. I have seen these sleeves put in a ferrari once before, they dip the sleeves in liquid nitrogen to get them to contract, a robot puts them into the engine where they expand and become permanent. Mechanics don't have these skills. If it overheats... pull over ASAP.

This is what happens to the piston in a 5 series when it overheats and you keep driving....

http://foreignaffairs.us/gallery/albums/userpics/10001/DSCF0026_1.jpg

Answer 5

How old? Usually a bad cooling fan, relay, clogged radiator or thermostat. If you buy the car in the summer, remove the thermostat and drive it, if the problem goes away, you found your gremlin.

Make sure the coolant is clean and properly mixed, too. Sometimes a failing water pump impeller is to blame. You can have a listen with a mechanic's stethoscope to determine its performance.

I wouldn't buy any car that's been prone to overheating. You might really regret it.

Answer 6

A bmw 5 seies is a huge vehicle for a 17 3 hundred and sixty 5 days previous. Its no longer a activities vehicle so i dont think of he would be racing it. its very reliable. BMW has many of the terrific warranties around. I wouldnt pass with mercedes ( to lots of an previous individual style) porche are badly made automobiles i do unlike them. Lexus is only a very good toyota. Get him a sturdy german made vehicle, the 5 series

Answer 7

Poor coolant circulation around the rear of the engine block, and owners who don't have the money/inclination to maintain their cars properly are the main suspects.

Cars that have blown the head gasket once will keep doing it unless the root cause is found: get a compression test done, and if it seems suspect, walk away. Make sure the car is inspected/serviced by someone who knows BMs.

Answer 8

don't do it,,,,, do NOT buy this car if it has regularly over heated then the chances are the head needs skimming and the gasket changing, if u still want to do this then phone "German and Swedish" they specialise in parts or German cars and also are v v v v good at telling it to u straight

Answer 9

check the belt/cooling fan.