engine overheating

[Robert63]

Hi All
I have a 04 plate e85 2.2 z4 . for a number of reasons the car has been stored in a dry garage. Only coming out once in January this year for its MOT which it passed with no problems. I am now in a position to put it back on the road which I have from the 1st of September. Eagerly I took it for a spin on the 1st only to find after approx 8 miles the engine completely overheated with the temp gauge in the red. I left the engine to cool down and checked the engine coolant level expecting the level to be low in the radiator, suprisingly it was full, so I am not sure as to what is causing the engine to overheat. Any ideas anyone. Many thanks Rob

 

[Smartbear]

Could be a blocked rad or a non functional water pump :?
Rob

 

[bigwinn]

Hi matey

If your water pump is original it could be on the way out- any unusual rumbling or rattling from front of engine?

 

[enuff_zed]

Possibly an airlock?
Was it really hot? Sounds silly, but was it a sensor issue or was the engine actually that hot?

And thinking more abstractly, are the brakes ok?
Binding brakes 'could' make the engine work harder, but I'd be surprised if you didn't feel it, plus see a fair amount of smoke from the wheels.

 

[Robert63]

HI Yes the engine was genuinley hot . Please excuse my ignorance but would anyone know as to how to get rid of a possible airlock.

 

[bigwinn]

HI Yes the engine was genuinley hot . Please excuse my ignorance but would anyone know as to how to get rid of a possible airlock.

Method I'd use is get the front of the car up on ramps or jacked-

Take the front splash cover off the engine, next to the water fill point there is a hose that leads from the radiator to the engine, on top of that is a bleed screw- undo that while the engine is running to release any air in the system

 

[enuff_zed]

HI Yes the engine was genuinley hot . Please excuse my ignorance but would anyone know as to how to get rid of a possible airlock.

Method I'd use is get the front of the car up on ramps or jacked-

Take the front splash cover off the engine, next to the water fill point there is a hose that leads from the radiator to the engine, on top of that is a bleed screw- undo that while the engine is running to release any air in the system

And to amalgamate Stuart's two replies so far, if you don't get water flowing past, or out of, that bleed screw, then you could have a water pump failure.

 

[enuff_zed]

Adding another thing to the list, if the engine does get hot, is the radiator hot as well?
Could be the thermostat stuck closed?

 

[bigwinn]

Adding another thing to the list, if the engine does get hot, is the radiator hot as well?
Could be the thermostat stuck closed?

100% on this

I'd be looking to find an air lock, faulty thermostat or water pump in the process

Assume belts are all OK? No warning lights?

Where you based Robert?

 

[Zulu4]

+1 for thermostat stuck closed.

 

[Robert63]

I think I will go down the road of an airlock first, and then take it from there . Iam based in Burry Port which is in West Wales

 

[Rockhopper]

These engines don't take kindly to overheating - I'd expect head gasket issues before too much longer.....

 

[enuff_zed]

I think I will go down the road of an airlock first, and then take it from there . Iam based in Burry Port which is in West Wales

Well while you're running it to try to clear an airlock, you can hopefully check out whether the pump is actually circulating the coolant.
And after a few minutes, if the block is getting hot, check the radiator too.
That way, after running it for just a few minutes, you should be able to do most of the diagnosis we've thought of so far.

Yup, West Wales................... you probably have some of our colonial cousins who are closer to you than I am in Norfolk. :rofl:

 

[colb]

I would certainly try bleeding the system first, check rad gets hot and thermostat opens by monitoring temp on live data diagnostics if you have that capability. Too bad I am in East Wales, Newport or I would have a look and plug it in to diagnostics for you.

 

[Andrew Sheldon]

Adding another thing to the list, if the engine does get hot, is the radiator hot as well?
Could be the thermostat stuck closed?

That was my 1st thought too..

 

[Robert63]

Hi all many thanks for all the help and suggestions I have now identified a small leak on the coolant expansion tank. This has now been replaced and overheating problems have now gone. Many thanks all.

 

[bigwinn]

Glad to hear its fixed- most people who have this issue dont notice immediately due to it being a very fine mist leak

Good job!

 

[enuff_zed]

Excellent and not too expensive.
I guess the initial leak is not so much letting coolant escape, but dissipating the pressure that holds the coolant below boiling point.

 

[colb]

Minor leaks can be difficult to find, I invested in a Vaccum Coolant Filler as I have a compressor in my garage, system is drained in the usual way via radiator drain tap or taking off the bottom hose, once drained the vaccum filler is connected to the car via the filler and by turning the appropriate valve on the tool the air is sucked out of the system, you will see the hoses collapse as the vaccum increases, once at the max vaccum the valve is turned and the vaccum guage on the tool is monitored to see if the vaccum remains stable over time. If it drops its a sure sign there is a leak somewhere in the system. A good ear may well direct you to the point of the leak so you can fix it. Once happy with a good vaccum the filler part of the system is used to suck your prepared coolant mix into the system. Worked a treat on a 1.9 Z3 I had in from a Forum member, no trapped air problems in the heater matrix that is often the case when manual bleeding. Kit I got was from ebay, just looked at current listings, most from China and prices seem to have gone up since I got mine.
https://www.ebay.co.uk/itm/302080227585?_trkparms=amclksrc%3DITM%26aid%3D1110006%26algo%3DHOMESPLICE.SIM%26ao%3D1%26asc%3D20201210111314%26meid%3D67609e65c30447faac8a8a983ebf2d1a%26pid%3D101195%26rk%3D5%26rkt%3D12%26sd%3D313455146056%26itm%3D302080227585%26pmt%3D1%26noa%3D0%26pg%3D2047675%26algv%3DSimplAMLv9PairwiseWithPLXWeb%26brand%3DUnbranded&_trksid=p2047675.c101195.m1851&amdata=cksum%3A30208022758567609e65c30447faac8a8a983ebf2d1a%7Cenc%3AAQAGAAACEPu7CbTpoii%252F0jflfjcq6%252BKYwjH0OvzXp4IeZopq%252BbMpuaBlOnPoxHTTmNZmaXdjeLQ2dZD4h3xY6WZaVxo908j5blFRpCrR%252BA1n52QPnkbkB87NL5wUnpw4yeipmHgAFwIOPvK7Chuo2eKX5bUakwuP6wj35jIBfIVJzrbf0Au0hw7CZIPerHcs9j5KkKXFcIILqjCWO3xtZ%252B3CHBajCy96Q2TdoRTX53sh2jQzRORMg%252FNBYjAHh4JZoeu5Fju4H2hefM54euXUUXnvCGLHsg8%252FdJo3c8c18LIr6LgzBAfR7XJW95pT161RqbolrBp4GuwzS9QpRTWhABoJVwqaTe0oHOqPl%252BVNmlcTfOxn%252F0eNbWNon8FZox0wjViDYo7cW%252BCzx45WKCY0B5SVhWKKVzE0KHofamOeYL3k0C7tCAfgSN%252FLsz5M2XBo0tWu3cHp22X%252B0dJ4d06IDCAXluaQPnRX7f8vyhJ0kP5Fis0s1D6r9vwExPXKoNhvIMi90%252BL%252FXizD35HuSK0ULfBj10y2et48%252BA2EMWN3pzcFYAHwbNL472bGzX0RxgcdsZpjCbZqHD9pMQqcdrSgd7wAhKbVFlLAK4%252BzeCdfuD%252FwNM0Ic%252FCtEjM68FFMbPkbVmaDXkL4S9FGDnQmL1GG4YlhC0Ha9jvfdc%252F0GvVo6ippjox8%252BZXyGaOFuZ3LKs2iL%252Fb%252BtNAtSA%253D%253D%7Campid%3APL_CLK%7Cclp%3A2047675