V6 ENGINE GURUS NEED HELP (noobs need not apply)

Mnemonic · Post by **Mnemonic** » May 22nd, 2007, 4:31 pm

K so I have had an overheating issue for the past 2 weeks that is litterally driving me insane, before the engine has had weird sparatic overheating issues in the past, but usually its an easy fix. But recently this one has stumped alot of us. Patdiesel and I have had several conversations on trying to figure out what the problem is, along with conversations with Barry (custommx3) who basically has gone through everything that pat has.

What i have checked/swapped/replaced:
Coolant Flush
Fan temp switch
Temp Sensor
Thermostat
Water Pump
Bypassed Heater core
Hoses
radiator
Fans
Pressure cap

There are no indications of a cracked block, warped head, or blown head gasket (though when i have a few little bubbles when i fill the system up, there is no coolant in the oil or, white smoke blowing out.)

This also happens on longer distances, short daily driving used to not be an issue (as of today it seems to be) when i say longer distances i mean about 25-30 mile +

Any help from anyone would be greatly appreciated, I'm already planning for the worst but Hoping that we have some how missed something

Tunes67 · Post by **Tunes67** » May 22nd, 2007, 4:57 pm

Brian.. PM me a phone #. I will talk with my machinist tonight and can give you a call this weekend.

In the meantime.. there is a tool you can get (I will find out the name of it) that will test your coolant for the presence of exaust gasses. If the coolant passes the test.. you know for certain its not a head gasket. And yeah.. you can have a blown head gasket that allows exaust into the coolant but coolant still wont get into the cylinders. You may need to take the car into a shop.. I know this process exists.. but for the life of me.. I cant remember how it works or what its called. I will find out tonight.

Another thing you can do.. get a cooling system pressure test kit. I have one.. so if you cant rent one or buy one (they usually run $75-$150 depending on the model) I can let you borrow it.. (damn right your paying for shipping though LOL)

Hook up the pressure tester and put the system under pressure.. (normal operating PSI) then start the car and let it run for a while.. get it good and warm.. varying the RPMS.. this will take a hour at least to simulate driving conditions. Watch the pressure gauge on the cooling system pressure tester. The pressure should not change.. it should remain constant.. if it rises above normal significantly or drops below significantly.. you have a head gasket problem. If you want.. I can take a couple of pics of my tester kit and show you how it hooks up. And I will talk with my machinist tonight and see what other ideas he can come up with to explain this or to test for. Cheers

Tunes67

Post by **Custommx3** » May 22nd, 2007, 4:58 pm

WTF, you called me last night and said you fixed it?

Tunes67 · Post by **Tunes67** » May 22nd, 2007, 5:01 pm

Couple of other things.. did you replace the waterpump? Check it? If so.. how did you check it?

Tunes67

Tunes67 · Post by **Tunes67** » May 22nd, 2007, 5:06 pm

Oh yeah.. one more question.. How are you determining that the engine is overheating? Is it overflowing the runoff tank? Factory gauge pegging at max? Aftermarket gauge reading to high?

Tunes67

Mnemonic · Post by **Mnemonic** » May 22nd, 2007, 7:00 pm

Justin (jaydog) and Pat (patdiesel) are coming over to the house Thursday to help me look over everything and to pressure test teh coolant system. The water pump has about 15k on it, we pulled it from my old kf which i only put 5k on before hurricane ivan destroyed it... When we looked at it it was in really good condition, and since then i have only put 10k on this motor...

This is actually really weird because when it over heats its the dash gauge temp going up into the hot, Note i am paranoid and watch my gauges like a hawk, when i see the temp gauge start to rise, even slightly above the norm, i pull off the road, Its only gone over the actual line into Hot Once and that was about a year or so ago. But the last couple of times its been overheating with zero water shooting out of the overflow res, and its maintain the accurate coolant level...

Well Barry i thought i did but the leak i found had to be caused recently probably the last time it over heated it must have burned the hose or something...

To be honest guys i'm litterally a few months away from graduating i'm doing a full load of school, finishing my portfolio, building my website, working full time, so my mind is slightly going... Thus the reason to bring people over to look cause i need a 2nd set of eyes and hands to focus on everything.

I'll Pm you my number

Tunes67 · Post by **Tunes67** » May 22nd, 2007, 8:01 pm

So when its overheated.. its only apparently doing so on the OEM gauge? Your not blasting coolant out the overflow resevoir? Time to install a aftermarket gauge and see if it acts the same way as the stock one.. My stock gauge in my old subaru did that to me..

I spent tons of $$$ thinking it was the water pump.. heater core.. radiator.. all it was was the stupid gauge had gone bad. So if you have no other obvious symptom of over heating.. get a cheap aftermarket gauge and get it hooked up and see what it says when the OEM gauge says your starting to overheat.

Tunes67

Mnemonic · Post by **Mnemonic** » May 22nd, 2007, 8:15 pm

now dont get me wrong it has done the whole overheated, pulled over, and there was coolant spraying onto the ground from the overflow resivour, it did that on the way to my moms house, so i filled it up with water. When i left and was almost home it started to rise again, only this time, it had a decent amount of water. I did a 6 hour flush, I ran the car for 3 hours while flushing it with a mixture of driving and idling (in the 3 hours car didnt overheat). Then i flushed it out using tap water, a few times, then flushed it twice with mineral water then filled it up with a mixture of Water, & water wetter (summer time Anti freeze not required). Well it overheated again and well i'm basically lost in whats wrong now, we think its a bizzar blockage or something wrong internally

Tunes67 · Post by **Tunes67** » May 22nd, 2007, 8:29 pm

Ok.. I'd still put a aftermarket gauge on it.. just so you can see actual coolant temps. But it doesnt sound like its just the gauge. Do the cooling system pressure test.. (leave it under pressure for at least an hour.. better if you can let it sit overnight even) and check to make sure it hasnt lost any pressure. Let it run with the pressure tester hooked up.. revving it a fair amount too so that if its pumping exaust gasses into the coolant.. the pressure tester will note it. And I will still talk with my machinist tonight and post back either late tonight or in the morning

Tunes67

hgallegos915 · Post by **hgallegos915** » May 22nd, 2007, 8:46 pm

well I see you mentioning everything except the fans? is the fan spinning fast? just a normal spin? have you tried running her with both fans on? other than that i cant see why it woulod overheat since you covered everything.. i dont think its the timing either since the ecu auto adjusts.. strange.. let us know your findings.

Mnemonic · Post by **Mnemonic** » May 22nd, 2007, 10:08 pm

the fans run they work i've swapped and swapped again, not fans...

Nd4SpdSe · Post by **Nd4SpdSe** » May 22nd, 2007, 10:36 pm

Fans are only necessary at idle and extremely low speeds. Moving even at city speeds moves more than enough air across the radiator to keep it cool. If it starts to overheat while he's driving, than I don't see no reasons to think is would be the fan(s).

Is there the possibility of something restricting/blocking the flow of coolant?

Zoso124 · Post by **Zoso124** » May 22nd, 2007, 10:41 pm

My first recommendation would be to change the thermostat again. I know its new, but I talked to an old time mechanic that told me he has put in replacement thermostats for sticking ones and have found that some new ones will stick shut.

I'm with Tunes the only other possibility I can think of is when the engine gets the hottest your leaking some exhaust gas into the coolant.

Mnemonic · Post by **Mnemonic** » May 22nd, 2007, 11:10 pm

this is an intresting thread with similar problems to what i'm having (so i am swapping the radiator as we speak)

http://forum.doityourself.com/showthread.php?p=1173120

Just hoping its not the headgasket....

Tunes67 · Post by **Tunes67** » May 23rd, 2007, 12:06 am

I just got off the phone with my machinist... and here are a few things.. This next paragraph is copied and pasted from this link...

http://www.troubleshooters.com/tlitthypothesis.htm

You can use a "Block Tester" to chemically determine whether there is exhaust gas in your coolant. These "Block Testers" are sold by NAPA stores for approximately $45.00. The quote I got from my local NAPA dealer was $45.99. He didn't have it in stock, but said he could have it the next day. The relevant NAPA catalog is called "The PSA 2000 catalog" or the "Balkamp Catalog". The catalog calls the Block Tester a "combustion leak tester kit", so that's probably what you should ask for. From what I understand, it comes with a ball, tubes, test fluid, aspirator bulb and engine adapter (cone shaped device you place in your radiator filler cap). If there's exhaust in your coolant the test fluid changes color.

Stop Leak = The Devil NEVER USE IT (I learned this the hard way too,:oops:)

Now as for the radiator.. possible its plugged.. and thats tough to check.. but radiators often lose their ability to conduct heat over time. Copper Core radiators are usually more prone to this (or it happens sooner with them) than aluminum core radiators. 8-12 years is about the maximum lifespan of a copper core radiator. Yes they will still flow and may not leak.. but they are no longer transferring heat as efficiently as they did when new. Now.. most car manufacturers take this into account and use a radiator that can afford to lose a bit of efficiency over the years. But sometimes.. (depending on the application) its not enough. Keep in mind that your radiator was designed to cool the K8 not a ZE. I am not saying run out and buy a new radiator.. I am saying its possibly contributing to the issue.

Coolant vs straight water. You should be running a 50/50 mix of coolant and water. Coolant has higher boiling point than straight water so it takes longer for it to start to boil. Also.. the greater the pressure on the coolant (water or coolant or mix of both) the quicker the coolant will reach a boil. Just like water comes to a boil faster at lower altitudes than at higher altitudes.. cause there is less atmospheric pressure on the water at higher altitude.

Your disconnected heater core. You should pressure check it to make sure its not leaking and reconnect it. Taking the heater core out of the system reduces the amount of coolant in the cooling system making it that much easier for the coolant to heat up quicker. Also the heater core can act as a mini radiator and help cool the coolant in emergency situations.. Yes it sucks to have to turn the heater on full blast in the middle of summer.. been there done that.. but it got me home

You should check and make sure your mixture isnt running too lean.. if you have a couple of plugged injectors.. that could lean things out a bit and that would help the engine heat up a bit more.. especially at idle. The ECU should be controlling the timing.. but it wouldnt hurt to check your base timing and make sure its in spec.. if the ignition timing is retarded.. this will also cause the engine to run hot. The ECU should compensate for that.. but its worth checking. Also check your timing belt tensioner for the same reason.

When you hook up that cooling system pressure tester on thursday.. try to run the engine and bring it up to normal ( or as hot as you dare) operating temp.. watch to see if the pressure of the cooling system rises as the temp rises.. the pressure should remain equal to or less than the PSI spec that is on your radiator cap. If you exceed that PSI spec.. then the engine is overheating (if the radiator cap was on instead of the tester adapter.. hot coolant would be headed for the overflow reservoir)

Anyway man.. I'll give you a call friday and go over this stuff with you and see what you guys find out thursday. I have a 4 day weekend this weekend starting friday.. so I should have plenty of time. Hope this stuff helps

Tunes67