So I bought a 2005 Pathfinder 4 wheel drive a week later it messed up, I replaced the radiator, thermostat, pressure coolant reservoir, fan clutch, but it’s still overheating at high speeds what could it be now?
With the engine cold, remove the radiator cap.
Start the engine, and as the engine idles watch the coolant in the radiator.
If bubbles begin to form, it indicates a blown head gasket.
Bring the engine RPM’s up.
If the the bubbles appear faster/larger, it is a blown head gasket.
Never replace radiator fans or fan clutches for overheating at high speed, There is plenty of air moving through the radiator then.
You could have low coolant level caused by not getting all the air out of the system or because pf a leak.
You could have a bad head gasket or cracked head or block.
Instead of throwing parts at a problem, it is better to diagnose it first. Do as Tester suggested and check for bubbles. rent a pressure tester at an auto parts store, most of them have free loaners. If the first two don’t lead to a solution, try a chemical test of the coolant to check for combustion gases.
If it is a mechanic that is throwing parts at this truck, get a better mechanic.
How does it perform at low speeds? Around town? Under 40mph? Stop and go trafffic?
When you say it overheats in only 1 setting it seems to imply that it performs ok in other conditions.
When I bought the vehicle the radiator started leaking it looked as if they had put a temporary sealant in it because it was full of sediment and what not, so I started changed out everything, I’m wondering if maybe some of this sealant got into the heater core and may have clogged it
I have put in a complaint to the tx dmv I was sold a lemon car, they had purposely taken out the oil light and the check engine light. And did not disclose any information of the sealant being put in the radiator he said the vehicle worked great. I got scammed $4000 for a hunk of metal
If the heater core is clogged, the heat should not work but that should not have any effect on the car overheating unless something else is wrong with the cooling system and you are running the heater at full blast to get the engine temp down.
I am sorry for your plight but now you see why you should pay a mechanic to check out a car before you buy it.
If you don’t pay a mechanic, one of the first things you should do is turn on the key without starting the car and make sure the oil pressure and check engine light come on.
Pf the seller won’t let you take the car to a mechanic, don’t buy that car.