JimmyT Posted February 17, 2015 Report Posted February 17, 2015 Hi all, My car, 2003 MKii 1.9tdi I changed my thermostat the other day as my heater was not working to well, reconnected eveything and the heater worked as it should. Then i decided to flush the system by removing the rubber hose just after the thermostat (about 4" from the block) , this pipe leads to the bottom of the rad. I put the garden hose into the expantion tank and flushed water through, reconnected and refilled system, did this twice, then filled with antifreeze / water mix. brought car to normal temp (90 dreegres) and the internal heater is working fine. The problem is the pipe form the thermostat to the bottom of the rad is cold and so is the rad. I'm guessing its airlocked,but it is meant to be self bleeding. I have done about a 100 miles in the car and everything seems fine, but the lower pipe never gets warm. Max ambent tempture is 10 degrees at the moment. any advice apperciated. Quote
chrispb123456 Posted February 17, 2015 Report Posted February 17, 2015 That is normal after coolant has passed through the radiator especially this time of year. Quote
JimmyT Posted February 17, 2015 Author Report Posted February 17, 2015 That is normal after coolant has passed through the radiator especially this time of year.So you don't think I have a fault/ airlock. I thought it should have at least been warm. Quote
chrispb123456 Posted February 17, 2015 Report Posted February 17, 2015 These engines really struggle to get hot this time of year this is why you have the booster heater underneath to aid warm up, The direction of flow is top to bottom, top of rad warm/hot and bottom of rad and bottom hose cool/cold. You have nothing to worry about. Quote
BrianH Posted February 17, 2015 Report Posted February 17, 2015 The petrol one I've got is the same - it barely gets beyond the n in normal on the gauge unless its sat in traffic for extended periods and then within 20-30 seconds of moving again its down to the cooler end. I think you will find the rear heater adds so much extra coolant into the system it never warms up enough to open the stat in colder weather like it is at the moment. Quote
xavier Posted February 18, 2015 Report Posted February 18, 2015 If you're heater isn't working too well check your auxiliary pump is working, if not you should find replacing the brushes in it a lot easier than doing the thermostat, and you don't have to drain the coolant system down. Quote
seatkid Posted February 19, 2015 Report Posted February 19, 2015 The problem is the pipe form the thermostat to the bottom of the rad is cold and so is the rad. I'm guessing its airlocked,but it is meant to be self bleeding. I have done about a 100 miles in the car and everything seems fine, but the lower pipe never gets warm. Max ambent tempture is 10 degrees at the moment. any advice apperciated. Its not a problem at all. Hot water goes out the top hose to the top of the radiator and flows down. At this time of year the bottom of the radiator and bottom hose should be cold. In winter, when youre using the heater, diesel engines struggle even to warm the the top hose up unless you're bombing down the motorway and have done at least 5 or 6 miles. The only thing to watch is the temperature gauge - if its showing normal, everything is AOK! Quote
JimmyT Posted February 21, 2015 Author Report Posted February 21, 2015 (edited) Thanks for all the replies. I got it into my head that the bottom pipe should at least be warm, so i came to the conclusion that it was airlocked. "Talk about looking for problems" :) Edited February 21, 2015 by JimmyT Quote
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