Hi, its not good news im afraid by you describing that with the coolant cap off and revving the car causes the pressure to build up and push the water back out it sounds to me like the head gasket is on its way out, what you need to do is take it to a garage and dont have a compression test done you need to have a gasses test done, you can buy these yourself if you want to and what it does is this.
its a plastic tube with blue liquid inside it then you take the coolant cap off and place this in its place you then run the engine and rev it up then you squeeze the rubber at the end of the tube and it then sucks the air out of the coolant and through this liquid then if it detects gasses from the engine in the coolant then this turns the liquid green and this is then telling you that the head gasket needs changing.
please dont let it keep over heating as this will cause the cylinder head to warp and you would then need to get it skimmed to make sure its not warped, get the gasses test done as a compression test dont give you a true reading as the engine is not running when they do a compression test.
let me know how you get on or if you need further assistance ok
plz rate this solution as i have a whole page of unrated posts, thanks
I bought a "block tester" kid and tested the radiator for exhaust gases and found none. Should the coolant erupt violently with the radiator cap off and the engine reved? The fans seem to come on and go off at too high a temperture. Like 200 and 190. Son-in-law says the cap for the overflow container has been blowing off. He thinks maybe the water pump is cavitating. Thanks for your help. Ned
Hi, if you have tested and their are no gasses then this would rule out head gasket failure, have you tested the thermostat to see if its opening to do this take the thermostat out and have a look at it so you can see it in its closed position then put some boiling water in a tub then place the therm in it leave it their for 1 min then take it out and see if it has opened up if it does then its working if it stays closed get it replaced as it is faulty.
no for the water pump, check thermostat 1st as its easier than removing the pump if its ok then i would go for the water pump chances are its fins have got corrosion built up on them and its not pumping the coolant as it should this does happen over time and it happens even quicker if you dont use any anti freeze in the coolant
let me know how you get on or if you need further assistance ok
make sure you have got all the air out of the system check in the big hoses running around the top of the engine for a bleed screw if their isnt one then it is self bleed system if you do find 1 or more then let all the air out then start the engine but leave the coolant cap off leave the car to tick over and when the temp reaches normal running temp put the coolant cap on then see if it still over heats.
Thanks again, I'm pretty sure the thermostat is opening properly as you can see the coolant start to circulate after it starts to warm up. Not sure what you meant about the water pump. (read your post). Should the coolant erupt violently when warm and the engine reved? I do wonder about proper circulation. A laser thermometer gives only about a 145 reading when pointed at the coolant (in radiator) when the thermostat housing reads 195 to 200 although both hoses are warm/hot. Is it possible to dissolve away corrosion on the fins without taking the pump off? Taking it off is a job we do not want to tackle as other posts indicate there is a part very difficult to remove without a special puller.
Hi no its not possible to remove corrosion without the pump off, what the corrosion does is it builds up between the fins then it stops the water flowing through the fins so it wont pump it round as it should so this would cause it to over heat.
check the temp at the top and bottom of the rad and see if their is any difference
Thanks again, Just checked temps of the radiator. There is an almost 30 degree difference top to bottom. Range of 180 top to 150 bottom.. Also checked temps of the thermostat housing. 10 to 15 degree difference each side of the thermostat even with the engine hot. Wonder if the thermostat IS opening. If the circulation is through the top hose then the radiator and back out the lower hose to the thermostat makes since that the coolant would erupt when the engine is reved and the thermostat isn't open. Ned
Just found out that the thermostat was just replaced. Does the wide variance in temps on the radiator indicate non-circulation as I suspect?
yes it does to me it seems the temp is building up in the engine and it could be the water pump is not pumping at 100% causing it to over heat a lot quicker, does the rad fan cut in at all before the coolant boils up?
the fan switch could need replacing
also how quick does it boil up does the water come bubbling out as soon as its started and then revved or does it only happen after its been running for 10min or so
I suspected the rad fan also so checked when it came on. It does come on but not till the temp is 200 and then cuts off pretty quickly at about 190. I have ordered another fan switch. The coolant does not start bubbling up till the engine is warm/hot.
The fan does run but not till the temp reaches 200 and cuts off quickly at 190. Only erupts on revving after warming up.
hi i keep getting emails saying i got a response from you but when i log in their is nothing their just your last post where you said the thermostat has just been replaced, please scroll down and contact fixya about this as its unfair if i cant get your response, thanks
I finally see my last posts above. Hope you can get them. Ned
hi yes i just managed to get them how are you getting on have you got any further have you looked at the water pump yet.
also the fan wont cut in until the car is about to boil over now as the system is under pressure it dont boil over at the usual 100c mark so its goes right up to the top of the gauge before it boils up
if your coolant filler cap is faulty then this could be causing it to over heat sooner as the system wont be under any pressure
let me know how far you have got ok
Hi, I installed a new fan switch and my son-in-law has been driving it to work for several days. A 30 mile commute in traffic and it has not overheated. My granddaughter just left to drive it back to college 150 miles so hope it's OK. I suspect it may not have the correct antifreeze so will replace it when she comes home. Would not cause it to overheat but hard on the aluminum engine if not the correct kind. Thanks again. Ned
great glad you got it sorted, make sure the anti freeze is 50 50 mix with water as this is best for the engine. may also be worth throwing some decent fuel line cleaner Red X is good brand to buy you can get it from most filling stations and car spare shops and you just pour it into the tank and it cleans all the fuel lines and injectors and reduces mpg so saves you money in the long term
×
715 views
Usually answered in minutes!
×