Coolant radiator problem...please help!!!!

[djtrip]

Hi Wondering if any one could help with problem?

I had a problem with coolant loss from cracked hose which i replaced along with coolant following Bwitched Blingo's video on youtube which i have done before without a hitch.

This time though the pipe from radiator didn't get hot so I bled system and replaced thermostat with new one...I then had a mechanic refill coolant but he just filled the system and drove till engine hot and heater working he said the system may have had air trapped and disconnected hose from heater matrix to allow it to escape along with what seemed most of the coolant, everything then seemed to be normal.
On the next drive the fuel gauge didn't seem to work so I opened bleed tube and header tank and tried to refill as per video then with engine idle and after revving engine for a while the gauge moved into normal position but pipe remains cold from bottom of rad and then the steam appearing from radiator cap!!! Is it a block in radiator as top is hot! not sure what to do next any help and advice gratefully appreaciated

[francophile1947]

It can easily take over half an hour for the thermostat to open, especially in this cold weather - the fact that the gauge is reading and the heater working is irrelevant. Bottom hose won't get hot until the stat opens. It is important to get the stat open before you have successfully bled the cooling system.

[Bob]

This doesn't sound good I'm afraid.

I can only suggest bleeding it as per the video and see how things are then.

If Bongy has overheated it is common for the head to fail.

[djtrip]

Thanks for the replies guys! I have been advised that it could be a blocked radiator and to pop 6 dishwasher tablets into the radiator and drive for a couple for day to see if this helps... has anyone heard of or done this? Concerned that if it doesn't work the engine will overheat and I will most definitely damage the cylinder head. What does anyone think?

[Simon Jones]

In correct operation, only about the top third of the radiator will get warm until the thermostat opens. You may struggle to get it up to opening temperature in this weather, but if you don't mind holding it about 2500 rpm for perhaps 10 - 15 mins to the point where the radiator fans come one, then you'll be about right.

I would certainly not consider putting any form of detergent into a cooling system. If you do have a blocked radiator you should change it and you will remove all the sediment that is causing the problem. I don't for one minute think a dishwater tablet which is designed to dissolve grease and fat will dislodge sediment, but if it did such that you spread it throughout the system, then you will have contaminated the rest of the system which considerably harder to replace than a radiator.

[mellon man]

Agree do not use any thing like dishwasher tabs
STP do a car radiator unblocker that should shift any sludge safely (not expensive) ..