Overheating problems

[gonzfonz]

I have been having overheating problems in my MR2 (a '92 3SGT-E), specially after being on the highway and running a constant speed of 80mph+. The overheating usually happens after being in the highway and driving in the city at low speeds. The radiator sucks all the water (3 liters of it or more) and overheats. The radiator fan works fine, I am not losing any water (no dripping or holes in the hoses or even the radiator) nor coolant. What can it be?

Also, I have my boost set up to 13psi, but sometimes (don't know why), the boost only charges to 9psi or 10psi and the car feels like if does not have any boost at all since it does not climb the rev's up fast as it should. Sometimes also my boost gauge shows 13psi but it seems as if the turbo does not charge at all (hence, it does not feel like a turbocharged car) and you can hear the turbine sucking air like crazy. Any ideas what can it be? The turbo hoses are fine and fit perfectly.

Help!

[lodownlv]

well thats cind of funny i deal with mazda all the time. well dude sorry to say your head gasket is blown and you head is probly warped 13psi would do that with a cheep or stock gasket

[JekylandHyde]

Originally Posted by lodownlv

well thats cind of funny i deal with mazda all the time. well dude sorry to say your head gasket is blown and you head is probly warped 13psi would do that with a cheep or stock gasket

What?! I am consistently run 22 psi on the OEM headgasket .... 100% original motor with 195,700 miles.
Many MR2 owners safely run 15 psi.
13 psi in no way means you are going to blow your headgasket.
If an MR2 engine goes, it is usually detonation damage to the rignlands, not the headgasket.

gonzfonz, you are probably expereincing knock:
http://jekylandhyde.madpowaz.com/knock.htm

I would make sure you have new Toyota cap, rotor and wires.
Also make sure to run at least 93 octance gas.
This should help your lack of top end power.

As fo overheating, it is extremely rare for MR2s to overheat ... I would make sure your coolant system is completely full and "Burped" as per the factory instructions. It is easy to get air into the system and even a small amount of air will cause consistent overheating.

Good luck.

[gonzfonz]

I have "burped" the car as said in the instructions, everything is original... the fan works fine, the radiator is fine, the hoses are fine, everything works... it just simply overheats... so now I am changing the full set of gaskets... that is the only other solution to my problem since any other possible problems have been disregarded... I hope this will fix my overheating problem...

[gonzfonz]

if anyone is having overheating problems and everything is okay (radiator fan, cap, sensor, etc), the problem is that you rhead gasket has blown... that is what has happened to me... confirmed...

[lodownlv]

it is most likely that your gasket is blown or you have a pressure loss somewhere it is a fact that overheating is caused by poor flow of the water pump or loss of presure! one thing to check is take off the radiator cap and start the car is the water jumping up and down in the radiator? if this is so you have a bad water pump. Smell and look at the water in the overflow dose it smell like gas, is their oil flowting at the top? if so this is a sure sign of a blown head gasket or even further damage sutch as worpage or cloged water propets. check these things and if you find nothing it would be best to have the car pressure tested to see if the cooling system has the correct psi for that model car. finaly a loss of boost would also be a sign of a bad seal around the head we are back to the head gasket :-)
let me know

[gonzfonz]

we are back at the head gasket... it has blown so I am changing it... hopefully that will be my solution to the problem... there is no oil or the water does not smell like gas... hopefully it is only the head gasket cause everything else has been revised...