98, audi 2.8 OVERHEATING

[quote:4ab2dc21dd="sandro"]I HAVE A 98, AUDI A6 WITH A 2.8 ENGINE AND IT HAS 125,000 MIL. wich is overheating the recnt parts that i replaced was the engine coolant tempeture sensor ( I replaced the coolant sensor becuse thats the only code that i recived from my diagnostic reader ) and i also replaced the thermastat and finally i replaced all of the coolant hoses.

as i drive the car on the freeway for about 15 min the heat gauge arrow stayes in the middle of it and whene i have to stop at a intersection the arrow markes hot but whene i get moving agian it goes back to the middle and when in done using the car it goes back to hot agian.


the diagnostic read is also reading a missfire, and in the same cylinder where it,s missfiring there is a leak of oil in the spark wire hole its not the gasket thats connecting the block to the head its anther diffrent gasket


what i replaced in this section of the engine is the spark plug the spark wires and tha coil assembley and finaly i replaced the battire

thanks[/quote:4ab2dc21dd]

Replace the thermostat and then comeback if needed.

thanks a hole lot for answering my qustion

but i have alredy replaced the thermastat just last month and i also replaced the coolant tempature sensor and all of the coolant hoses.

thanks

[quote:1529f80694="sandro"]thanks a hole lot for answering my qustion

but i have alredy replaced the thermastat just last month and i also replaced the coolant tempature sensor and all of the coolant hoses.

thanks[/quote:1529f80694]

Could be the Stat, run the engine w/o it and see what happens-don't work do below:

Have it block and pressure tested-do the block first to pinpoint a combustion leaking into the cooling system or a gas analyzer to sniff for hydrocarbons at the radiator fill neck.

Pressure test: do not do a pressure test if there's leakage at the headgasket this might cause coolant into the cylinders and lock it up or bend a connecting rod if cranked thereafter. The headgasket should be repaired before doing the pressure test.

If the block and pressure test passes check the following: Thermostat,Pressure test the Rad. cap,Clogged radiator,Fan clutch,Radiator electrical fan,collaspe hoses,water pump.

thanks for replying agian

so what does (stat) mean

and would you know how much it will cost for the block and pressure tests or is ther a way you could do it yourself
and what are the singh of a blown head gasket

thanks

[quote:7337ed271c="sandro"]thanks for replying agian

so what does (stat) mean: Thermostat

and would you know how much it will cost for the block and pressure tests or is ther a way you could do it yourself: Block chek is a fluid tester that changes color when there's hydrocarbons is present in the cooling system meaning combustion gases entering the cooling system: Pressure test will point where the leaking is coming from.

and what are the singh of a blown head gasket:

White smoke on the rear/coolant in oil or oil in coolant. If the engine overheats, the first thing that will happen is a gasoline engine will start to detonate ( meaning like a bunch of marbles being drop in a tin can) that's how it sounds. The engine will ping and start to lose power under load as the combination of heat and pressure exceed the octane rating of the fuel. If the detonation problem persists, the hammer-like blows may damage the rings, pistons or rod bearings then you need a new engine.

Detonation/Spark knock/Pinging they all mean the same thing.

thanks[/quote:7337ed271c]