radiator problem?

[zadam123]

I have a previous post called overheating is back which discusses in detal my overheating problem but its getting kind of long and i have a specific question now.

in a nut shell this is my symptom and what i have done.

My car overheats on the highway, the hotter the day the faster it overheats, also the harder i drive the faster it overheats, if my car is warmed up like 5-10 mminutes i can last like 2 exits on the higway at 70 mph berfor it goes to the H line on a 95 degree day

this is what i replaced, thermostat 4 times including the last one being a OEM, cluthch fan, upper hose, radiator cap.flushed the system thouraly 3 times, heater core and water pump replaced around 50,000 miles ago and doesnt make any noises and was told by mechanic it was good.

Here is my question, the mechanic is now telling me it may be the radiator, is there definate test to determan this? I am tired of all the guessing

thnks

[VX KAT]

From your overheating thread:
http://www.vehicross.info/forums/showpost.php?p=230879&postcount=4

[IndianaVX]

If you are not Loosing coolant, I would think radiator ......considering you have pretty much covered everything else! (other than head gasket, which you would be Loosing coolant)

Have you EVER used a stop leak product???? If so, it may have stopped more than a leak.....

[zadam123]

I have never used stop leak but looks like im going to try to replace the rad.

Does anyone know how easy this is? is there any tricks i need to know?

[circmand]

pretty easy to do or have done. Boiling out the radiator is also an option but replacement radiators on ebay have been inxpensive

[phines]

Zadam, you're jumping through all the same hoops that I did. I had the EXACT same problem. I replaced my radiator too and it didn't fix the problem. Did you ever check those head bolts?

[zadam123]

Zadam, you're jumping through all the same hoops that I did. I had the EXACT same problem. I replaced my radiator too and it didn't fix the problem. Did you ever check those head bolts?

mechanic told me if the head bolt was broken it would have failed the compression leak test i did, not sure now if it is true since he said it was definatly the thermostat
video here
http://www.youtube.com/watch?v=X05PDw5IE1U

[ojmagg]

I have a similar issue...mine seems to start to overheat when I turn on the air...I too have replaced the fan clutch, thermostat, flushed the system, O2 pump...I'm not loosing any fluid

[ojmagg]

I've an appt with a really good shop here in town...I play soccer w the owner...we'll see what they come up with...only prob, it's going to about 10 days till I can get in...I'll post back then...

[vt_maverick]

Did you read this thread on aluminum radiators? If you do find that you need a radiator, maybe this would be a good investment? I dunno how much they cost vs. OEM/aftemarket though.

http://www.vehicross.info/forums/showthread.php?threadid=20866

[dsallade01]

A failed water pump will cause the engine to heat up at speed, where as if it is a radiator issue or fan issue etc. the engine will normally cool down going down the road and heat up at idle. Water pump symptoms are almost completely reverse other overheating problems. Just my two cents.

[dsallade01]

I just replaced my radiator last week because the top plastic tank seperated itself from the aluminum tank. I guess what I'm saying is these things seem to have a few issues with the cooling system from what I am reading.

[phines]

mechanic told me if the head bolt was broken it would have failed the compression leak test i did, not sure now if it is true since he said it was definatly the thermostat
video here
http://www.youtube.com/watch?v=X05PDw5IE1U

Yeah, my mechanic didn't believe it was the problem either. But after a trying everything else, we decided to replace the head gasket. That's when we found the problem.

Not sure the compression test will show anything unless you do it after running the engine pretty hard and do the test at higher rpm's.

[zadam123]

Not sure the compression test will show anything unless you do it after running the engine pretty hard and do the test at higher rpm's.

when i did the test i did rev the engine to see if at high rpm it would fail but still passed the test. I am going to take the rad off this weekend and have it testted by a radiator mechanic