alright so i have a huge headache from this problem.... to begin my car was fine one day and the next day it began to overheat. I have an 88 dx hatch with an obd1 ls that i rebuild and has all new parts including cooling system parts such as fan switch(on water outlet), thermostat and water pump. radiator is about one year old. so my car began to overheat one day and i noticed that my fan wasnt turning on. so i trouble shooted it and fuses were good, relay was good and fan was good. so i replaced switch. fan still would not turn on so i replaced relay. still fan not coming on. so then i ran fan all the time and car would still overheat. so i said hey maybe thermostat isnt working so i changed it. still the car over heats. so water pump is only 2 months old. could that be why car overheats or is it the radiator? it isnt headgasket because no sign of my car consuming coolant such as drop in coolant level or white smoke from exhaust. i need some help please

 

well is there coolant? if there is air pockets in the coolant then it can cause it to heat up and not cool properly. but not to a high amount. iduno just an idea

 

yes there is coolant, and there might be air pockets but i mean car heats up to redline.

 

You have any coolant in the oil?

 

no i dont think so .....why would i have coolant in oil?

 

if your oil has the consistency and color of a chocolate milkshake, but lacks the delicious taste, then this would be a sign of coolant in your oil and ipso facto, a blown hg.

you can have your coolant tested for the presence of hydrocarbons and that will tell you if combustion gases are getting into the coolant system.

 

yea but i really dont think its the hg......wouldnt i smell coolant burning? and like i said my motor is not consuming coolant

 

you would not necessarily smell coolant burning no. however if it was burning it you would expect the coolant level to change over time. it would either be getting into the crankcase (leading to the milkshakey oil) or being burnt through the exhaust which usually leads to white smoke, but not always. either way if the coolant level is remaining unchanged i to would think that the hg being blown is probably not likely. with the cap off and the car warmed up, have you looked into the radiator to see if the coolant is flowing? you should see it moving from left to right.

 

no coolant doesnt seem to be flowing but i pressure tested radiator and it was fine.. i did find leak with pressure test on upper radiator hose...turned car on with fan on all the time and still overheated. so im really thinking its the waterpump..... but like i said thats weird because its new. but when i finished thermostat and filled radiator and bled it as much as possible air bubbles did rise to radiator. im swaping pump tomorrow but i want to hear ur ideas.

 

what kind of rebuild did you do to the motor and what kind of headgasket did you use? what brand?

 

Full rebuild...new rod and main bearings new piston rings.... hot tanked block, machined head and block...valve job...new felpro gaskets and seals (Head gasket TB gaskets water outlet etc.....) new timing belt new water pump, new oil pump, new oil pan, spark plugs and wires and rotor and cap. New clutch and pressure plate. New axles...and I'm sure there is more....oh and it was all autozone brand duralast pumps and belts.

 

did you make sure to mix the correct amount of coolant and water? thats a possibility

 

honestly not that likely. if you have improperly mixed coolant (overly diluted with water) then you should still not see the car overheat that much, if any at all. i can say from experience that i have overly diluted my coolant once before and it started to boil, which caused the steam to rapidly bubble through the overflow tank. at no point did it overheat though.

because this just started all of the sudden, it makes a huge air pocket and improper coolant mixture that much more unlikely. so at this point with no signs of coolant moving i would have to say it makes most sense to switch out the water pump for a new one.

 

Ok now does that explain why my fan still doen doesn't work? Like I said fan switch is on water outlet after thermostat, so if pump doesn't circulate coolant than that would mean that hot coolant never reaches switch and therefore doesn't not signal fan to come on right? I'm changing pump in morning so I will update

 

Is the lower radiator hose just as hot as the upper radiator hose when it is up to operating temp? If not then you are looking at a water pump or some sort of blockage in the cooling system.

 

Ill double check right now before I change water pump...now if lower hose is hot and upper isn't can that be a blockage in radiator?

 

Yes it could. It flows from Right to Left in the radiator.

 

ok so here is newest update... i ran car and upper radiator hose gets hot but lower stays cold, so im guessing its the pump. i will update after i change pump

 

well looks like you are heading in the right direction then. Hope it works out for you! Good Luck!

 

thanks so i just took off water pump but check this..pump looks fine. how do you know when its bad? it didnt leak before and the pulley spins really easy compared to the new one i just bought last night. how do i know its bad?

 

Intake manifold gasket.

 

alright so check this out...just replaced water pump and problem is still there...car still heats up...and lower radiator hose is still cold.....can there be a blockage in the rear water tube between water pump and thermostat?

 

i reckon it could be possible. it just seems so odd that all the sudden you would have a massive blockage preventing the coolant from circulating.. if you know the pumps good, and you've replaced the thermostat then really you're only left with some sort of blockage in the system. perhaps your radiator is clogged?

if you cannot find a blockage then perhaps it really is the head gasket that is shot. i had a blown hg on my mustang some time ago and it behaved in a way that your describing. it would constantly overheat, and coolant would not circulate. i did lose some coolant but it generally would take awhile for a noticeable amount to be missing. i did not have white smoke coming out the tailpipe nor did i find coolant in the crankcase.

 

so if i remove thermostat from water outlet, that would eliminate and blockage between radiator and water pump right? and if i do that then shouldnt my lower radiator hose become hot after motor warms up? im gonna try that and let you guys know. but please help me out with more ideas

 

d16si ur right but if i had a radiator blockage wouldnt my lower radiator hose still get hot?