87 MR2 Overheating Problem - Toyota Nation Forum : Toyota Car and Truck Forums

zman8537 · 01-04-2007, 10:13 PM

Help!! Sorry, kinda long story but I want to get all info out about this as I can.
Bought an 87 MR2 for kid that needed an engine, picked up a newer JDM engine, I had to switch over some things and had to use some things that didn't match up with the original engine. I installed a new head gasket, water pump, timing belt, and some other things that would be beneficial while the engine was out of the car. Original engine had a blown head gasket and ruined the engine. Put the engine in the car and ran for a couple hours sitting and idling and driving for about 5-10 miles everything seemed OK. I heard the front cooling fans run while it was sitting idling. Assuming all was good I then let kid take it and he drove it for a bout a week when the alternator belt burnt off of it I believe it was the alternator that went bad. (I am not sure how long he drove it without a belt) he replaced the belt and drove it about another week and the alternater shit the bed. I helped him change out the alternator and now it is constanly overheating. Here is the thing that really worries me, if you start it up cold or hot with the radiator cap off it will puke anti-freeze out, but I pulled the radiator our and rigged up a clear piece of hose up to see how much it was circulating (this is with the thermostat out) and it doesn't circulate up through the radiator at all. I flushed the system with a hose up through the radiator and then back flushed the radiator and all appears good.
I would sure think that with the thermostat out, that it should circulate up through the radiator, but again what scares me is that if you take the radiator cap off and start the engine it will puke anti-freeze out so if the water pump would be bad and wasn't pumping then why would it be puking anti-freeze. There is no sign of any anti-freeze in the oil, that still looks good. I AM AT A LOSS!!!! I know there are alot of posts here that says that bleeding the system on these is really crucial, I don't know, I really thought I had it bled pretty well. Any thoughts out there????????? I am going to try a new water pump and see if it will circulate as the engine will overheat and the radiator will still be cold, so I don't know!!!! HELP!!!!!!! Ron

cantalibre · 01-05-2007, 04:49 AM

Quote:

Originally Posted by zman8537

Help!! Sorry, kinda long story but I want to get all info out about this as I can.
Bought an 87 MR2 for kid that needed an engine, picked up a newer JDM engine, I had to switch over some things and had to use some things that didn't match up with the original engine. I installed a new head gasket, water pump, timing belt, and some other things that would be beneficial while the engine was out of the car. Original engine had a blown head gasket and ruined the engine. Put the engine in the car and ran for a couple hours sitting and idling and driving for about 5-10 miles everything seemed OK. I heard the front cooling fans run while it was sitting idling. Assuming all was good I then let kid take it and he drove it for a bout a week when the alternator belt burnt off of it I believe it was the alternator that went bad. (I am not sure how long he drove it without a belt) he replaced the belt and drove it about another week and the alternater shit the bed. I helped him change out the alternator and now it is constanly overheating. Here is the thing that really worries me, if you start it up cold or hot with the radiator cap off it will puke anti-freeze out, but I pulled the radiator our and rigged up a clear piece of hose up to see how much it was circulating (this is with the thermostat out) and it doesn't circulate up through the radiator at all. I flushed the system with a hose up through the radiator and then back flushed the radiator and all appears good.
I would sure think that with the thermostat out, that it should circulate up through the radiator, but again what scares me is that if you take the radiator cap off and start the engine it will puke anti-freeze out so if the water pump would be bad and wasn't pumping then why would it be puking anti-freeze. There is no sign of any anti-freeze in the oil, that still looks good. I AM AT A LOSS!!!! I know there are alot of posts here that says that bleeding the system on these is really crucial, I don't know, I really thought I had it bled pretty well. Any thoughts out there????????? I am going to try a new water pump and see if it will circulate as the engine will overheat and the radiator will still be cold, so I don't know!!!! HELP!!!!!!! Ron

If it overheated while the alternator was playing silly burgers, you could well have an air lock. Or did you bleed the system again after sorting the alternator? If so, there is a 'correct way' of bleeding. Sorry if this is already basic knowledge, but Toyota make a big fuss of it in their service manual!

tHa kNiGHt FaLL · 01-06-2007, 06:29 AM

good luck on that kid.

first thing you should have done when the engine was out the car was strip it down and check it out for thermal damage.

cause if the head gasket "ruined the engine" wtf did you put it in w/o rebuilding that bish.

to me your not giving enough info.

for the alt to be spinning belts and locking up the pulley the drive pully must have something wrong w/ it.

to me you didn't look over the motor well enough before the installation

zman8537 · 01-06-2007, 09:49 AM

The engine that was in the car was ruined from the head gasket going bad, I scrapped that engine. This is a JDM engine that I picked up and I replaced the head gasket, thermostat, timing belt, water pump, seals, gaskets and all the stuff that I could think of that might go bad and now would be the best time to replace rather than struggling with it in the car. Sorry if I was not clear on that. I am going to try bleeding again today and if that doesn't do anything I will try replacing the water pump. Still looking for suggestions though!!! I really don't want to pull the engine again. Ron

tHa kNiGHt FaLL · 01-07-2007, 01:54 AM

ok... go step by step... what it takes to make the car overheat.

idle, highway, uphill, immediately...?

KensMR2Parts · 01-08-2007, 11:45 AM

Greetings ... if "it will puke anti-freeze out" as you indicate, my fear (and I'm sure yours as well) is that it overheated when the alternator belt was off; and the headgasket has failed ... the quickest way to check/verify/eliminate this condition is to check and see if there are hydrocarbons coming out when "it will puke anti-freeze out" ... I believe PA is an inspection state ... if so, do they test exhaust emissions; that is the tool to use ... simply sniff the coolant (not the fluid, but the air coming out)(fill cap off, engine running) ... if hydrocarbons are present, the headgasket has failed ... it is possible for this to happen and have no coolant in the engine oil ... and this will also upset the circulation because now the engine is pumping air into the coolant system and it will never be bled ...

please don't be ill with the messanger

if this is the problem ... just trying to share an absolute method of diagnosis ...

regards ... Ken