rob83ke70 Posted June 21, 2010 Report Posted June 21, 2010 not a toyota corolla, but still a toyota: engine at operating temperature or maybe above, top radiator hose quite hot, bottom radiator hose cold or close to cold. bottom of radiator is also quite cold - engine seems to run hot.... could this indicate blocked cores internally in the radiator? Robert. Quote
altezzaclub Posted June 21, 2010 Report Posted June 21, 2010 or a waterpump not working very well.... The hot water has to be forced down a radiator, as it will normally stay on top of cold water. Go fire it up and watch for swirling currents with the cap off... :jamie: or can you put a garden hose wrapped in a rag in the bottom rad inlet and have water pour out the top inlet quite easily?? Quote
rob83ke70 Posted June 21, 2010 Author Report Posted June 21, 2010 might have a quick play with the radiator - water pump is brand new - its my pet dyna..... kind of in bits at the moment anyway, I'm deciding whether to get a radiator place to pull the radiator apart and clean the cores..... I've cleaned the radiator externally and straightened the fins which took at least 8 hours! it seemed to build a terrific amount of pressure up when it was running, and it would over pressurize and dribble all its coolant out of the overflow. I pulled it back apart and I'm not 100% convinced it was the head gasket now!! stupid cars!! Quote
altezzaclub Posted June 21, 2010 Report Posted June 21, 2010 Stick a hose up its bottom and see how fast it flows. I assume you flushed it last time you had it out.... maybe a lot of core tubes have been crushed. I wonder if it was pump pressure over-pressurising it or temperature?? So, the radiators blocked so the engine runs hot and then burns oil and really there's nothing wrong with the motor at all you've just pulled it apart for nothing when you just need a new rad core! Quote
rob83ke70 Posted June 21, 2010 Author Report Posted June 21, 2010 core tubes don't look that bad..... I'll get a radiator place to disassemble it and have a gawk and clean it and we will see. its been flushed quite a few times since I've owned the car.... motor had some bad noises and oil pressure issues as well - I wasn't happy with the rebuild. I'm going to measure it up and probably put new pistons/rings in it, and new main bearings and thrust washers at least.... Robert. Quote
rob83ke70 Posted June 21, 2010 Author Report Posted June 21, 2010 all you kids with corollas doing engine rebuilds - better to take months and months and spend all your money on it that to do a not quite satisfactory job and have to re do it!! Robert. Quote
e70van Posted June 21, 2010 Report Posted June 21, 2010 is the thermostat housing on the motor located at the top hose or bottom radiator hose? thermostat might not be opening..? Quote
rob83ke70 Posted June 21, 2010 Author Report Posted June 21, 2010 bottom radiator hose - new thermostat too! Quote
LittleRedSpirit Posted June 21, 2010 Report Posted June 21, 2010 bottom radiator hose - new thermostat too! Did you test it? they fail at any age. Quote
Felix Posted June 21, 2010 Report Posted June 21, 2010 (edited) Always pays to boil a suspect thermostat in a pot of water with a thermometer to check it opens properly. Also cutting the centre out of a thermostat (ie. only the moving piston part) , and temporarily reinstalling is a good way to rule out thermostat problems. Keep the main body part for the flow restriction to slow down the water flow. Edited June 21, 2010 by Felix Quote
ke70dave Posted June 21, 2010 Report Posted June 21, 2010 it seemed to build a terrific amount of pressure up when it was running, and it would over pressurize and dribble all its coolant out of the overflow. I pulled it back apart and I'm not 100% convinced it was the head gasket now!! stupid cars!! this to me tells me that you have air in your cooling system. water doesnt expand when you heat it, but air sure does! so if you have air in your system, and especially if this air is around your thermostat, that could be your problem. Quote
Taz_Rx Posted June 22, 2010 Report Posted June 22, 2010 If you have a hot top, and a cold bottom of the radiator (way it should be) then I don't see how this translates to a faulty/blocked radiator!! I mean if it was just as hot in the bottom as it was in the top then I WOULD point the finger at the rad. There is something else (in the motor) that is blocking the flow of water, and this is causing the hose to feel very hot by the time it exits the motor. The first thing I would be checking is the thermostat (even if its new) as mentioned above. Try and run the motor without it and see if it still overheats. As ke70dave said above, air pockets in the cooling system can really play havock. They'll reduce effientcy and get it hot, as well as cause extra pressure like dave explained. Quote
philbey Posted June 22, 2010 Report Posted June 22, 2010 and just to make it clear, water DOES expand when it gets hot, that's exactly what an overflow tank is for. Just not as much as a gas. When you say it runs hot Rob, do you mean it's always boiling? Or it just seems to be hot all the time? I've noticed that my top hose gets quite hot long before the thermostat actually opens on my KE16. Probably due to the trickle past the thermostat and some conduction as well. Quote
rob83ke70 Posted June 22, 2010 Author Report Posted June 22, 2010 I think I need an accurate temp gauge..... by runs hot, I mean the factory gauge made it to the red a few times and seemed to run higher than it should. the viscous coupling fan seemed to run more often than it should too - its brand new, the old one was seized solid and horribly noisy!! I was sure I had every last little bit of air out of the system too! I reckon its worth getting the radiator cleaned out anyway, and testing the thermostat and possibly even putting 5 degree cooler thermostat in it. the motor is 400cc larger than the original and the radiator is still stock. Robert Quote
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