mpower
September 23rd, 2009, 22:02
Ok so heres the deal, on my 05 tacoma v6 4x4 I am having some small cooling issues.
Past couple of summers I haven’t had any cooling issues even after adding a prerunner bumper and big trans cooler. So now all of a sudden the past couple of months ive been having these small intermittent problems with low speed cooling mainly.
First off I monitor my temps with a dashhawk , which is hooked up to the obd port. The past couple of years my temp usually hovers around 192* with the max ive seen throttling it up mountain grades in the dead of summer at 208*. Now lately its been around 195-200* and when I am stopped at a light for awhile after getting off the fwy it starts moving up to 210* real quick . when I start moving or raise the idle 500rpm everything cools down .toyota calls for a operating temp of 185-212* and up to that point the needle on the dash stays where its supposed to . but when it starts climbing up to 220-230 the needle starts moving toward hot and I shut it down(I know its not the smartest thing to do but its only happened twice and I kind of panicked when it started to get that hot)
so I replaced the fan clutch with a brand new oem unit after that .
Went out to Lucerne last holiday weekend and started having same problem again , but at night everything was fine no problems ? so when I got back I replaced the water pump, thermostat , rad cap, hoses and flushed rad the best I could.
Now that was fine for a few days until I made a trip to ft Irwin area last fri night. And started to get the same symptoms again . but on top of that I noticed that my reservoir keeps overfilling and puking up coolant every now and then ? popped the rad cap while truck was running and noticed medium sized bubbles intermittently come up to the surface. I immediately thought head gasket.
So today I preformed a cooling system pressure test ( leaked down maybe a 1/2psi in a 15min time frame)
Also preformed a hot cylinder compression test and all those results are very good??
Tomorrow im getting a cylinder leak down tester, ir thermo gun to test rad and a vacuum fill kit to make sure I got all the air out. If that fails to yield any results I guess my last indicator of a leaking head gasket would be to use a 5gas to analyze what the air bubbles are made from.
Other that that im stumped . I really don’t think it’s the head gasket , and. its just something that I really don’t want to have to do at 80000 miles. ive talked to 4 toyota service managers today and all of them said they haven seen 1 hg failure on the new 4.0 and one service manager said there was one overheating issue that only a new rad fixed. if I get a new rad its gonna be a pwr unit and im afraid that if that’s not the problem it will only mask the problem im experiencing.
Hoping someone could have some useful info that might help
thanks , mike
Past couple of summers I haven’t had any cooling issues even after adding a prerunner bumper and big trans cooler. So now all of a sudden the past couple of months ive been having these small intermittent problems with low speed cooling mainly.
First off I monitor my temps with a dashhawk , which is hooked up to the obd port. The past couple of years my temp usually hovers around 192* with the max ive seen throttling it up mountain grades in the dead of summer at 208*. Now lately its been around 195-200* and when I am stopped at a light for awhile after getting off the fwy it starts moving up to 210* real quick . when I start moving or raise the idle 500rpm everything cools down .toyota calls for a operating temp of 185-212* and up to that point the needle on the dash stays where its supposed to . but when it starts climbing up to 220-230 the needle starts moving toward hot and I shut it down(I know its not the smartest thing to do but its only happened twice and I kind of panicked when it started to get that hot)
so I replaced the fan clutch with a brand new oem unit after that .
Went out to Lucerne last holiday weekend and started having same problem again , but at night everything was fine no problems ? so when I got back I replaced the water pump, thermostat , rad cap, hoses and flushed rad the best I could.
Now that was fine for a few days until I made a trip to ft Irwin area last fri night. And started to get the same symptoms again . but on top of that I noticed that my reservoir keeps overfilling and puking up coolant every now and then ? popped the rad cap while truck was running and noticed medium sized bubbles intermittently come up to the surface. I immediately thought head gasket.
So today I preformed a cooling system pressure test ( leaked down maybe a 1/2psi in a 15min time frame)
Also preformed a hot cylinder compression test and all those results are very good??
Tomorrow im getting a cylinder leak down tester, ir thermo gun to test rad and a vacuum fill kit to make sure I got all the air out. If that fails to yield any results I guess my last indicator of a leaking head gasket would be to use a 5gas to analyze what the air bubbles are made from.
Other that that im stumped . I really don’t think it’s the head gasket , and. its just something that I really don’t want to have to do at 80000 miles. ive talked to 4 toyota service managers today and all of them said they haven seen 1 hg failure on the new 4.0 and one service manager said there was one overheating issue that only a new rad fixed. if I get a new rad its gonna be a pwr unit and im afraid that if that’s not the problem it will only mask the problem im experiencing.
Hoping someone could have some useful info that might help
thanks , mike