Murphy's Law

JD1964 · Dec 12, 2015

Day and a half from scheduled dyno testing and the thing starts puking coolant out the overflow bottle.

I think it's the thermostat not opening. I just changed it not long ago. Maybe I put a crappy one in there, I don't know.

So I don't make the same mistake, what is the most trustworthy T-stat brand? I'm going with 180 degree.

Black1987 · Dec 12, 2015

I usually run Stant without an issue. However, I always verify the temperature with a boiling pot of water on the stove. Sometimes the wrong temperature gets misplaced in packages or people return the wrong one in the wrong box. Either way, cheap insurance

JD1964 · Dec 12, 2015

Black1987 said:
I usually run Stant without an issue. However, I always verify the temperature with a boiling pot of water on the stove. Sometimes the wrong temperature gets misplaced in packages or people return the wrong one in the wrong box. Either way, cheap insurance

Usually the t-stat itself is stamped with the temp. But I have used the pot of water on the stove to check for bad thermostats. I put a rod across the top of the pot and suspend the thermostat on a wire. This keeps it off the bottom of the pot so the stove burner won't influence the test.

jchav02 · Dec 13, 2015

I'm having the same issue. Similar combo cobra intake, gt40 heads, tfs 1 cam, and a V3 Si running about 10 psi. After a few wot runs it starts shooting coolant out the overflow and overheats. Usually when this happens it means a head gasket has blown, but sometimes you get lucky and its a radiator cap, or thermostat.

elarm1 · Dec 13, 2015

This was my indication of my HG being blown. Check the plugs but chances are, its smoked! I will be getting with @84Ttop to see how this can be prevented in the future. Are you using ARP studs by any chance? What are their torque specs? What HG's? My car got abnormally warm which I believe contributed to my problem but what happened with yours? I'm running Felpro 9333's

JD1964 · Dec 13, 2015

I have Felpro gaskets (not sure the number) and I re-used the stock head bolts. The GT40 heads were milled .010 and magnafluxed crack free when installed. Thoroughly chased the block thread holes with tap and wire wheeled the bolt threads and followed all other required sealing and lubing of threads when installing. Tq to stock specs. Been running this combo for over a year prior to the V3 install with no issues. (not to suggest the V3 is related to the problem)

On mine, the temp gauge started fluctuating higher and lower but never overheated. When I checked the coolant level it was about a gallon low. Then, I found coolant drips hanging off the bottom of the gas tank cover so obviously it puked. After filling the coolant and letting it warm up to operating temp while idling everything seemed fine. Then I took it for a test drive and put the hammer down a few times. It puked again. Judging by the area of the mess, the coolant must be rapidly expanding under heavy load and blowing out of the overflow.

I filled it back up and checked for any major leaks again but found non externally. Got out the IR thermometer and while running at operating temp idling checked the temp at the intake just before the T-stat, and at the radiator directly next to the upper hose connection. At the T-stat housing 185 degrees, at the upper hose to rad connection 125 degrees. I'm hoping this indicates the coolant from the engine is not circulating into the rad (bad T-stat). I mean, how could the temp difference between those two places be 60 degrees if the coolant is flowing like it should be? There's no way the coolant temp drops 60 degrees just by flowing through the upper hose. Anyway, while testing at idle I'm assuming the heater bypass was moving just enough coolant through heater core to not let it over heat at idle but that surely wont stand up under heavy loads so thats why its puking when pushed harder.

In considering the possibility of a head gasket blown, I have a question. If everything else is good, coolant is the correct level, engine running great with no missing or any other recognizable conditions, how does the bad head gasket cause a sudden expansion of the coolant enough to make it puke? I understand over time a bad head gasket can consume the coolant through combustion and once the level gets low the engine overheats resulting in expansion. But, with full coolant and everything else good, I'm struggling to realize how a head gasket leak would cause a sudden expansion. If I'm unaware of or missing something, please school me.

elarm1 · Dec 13, 2015

Combustion is entering the water jacket of suspect cylinder. Take the radiator cap off and smell it. If it smells like combustion and not coolant, there is your issue @John Dirks Jr

JD1964 · Dec 13, 2015

elarm1 said:
Combustion is entering the water jacket of suspect cylinder. Take the radiator cap off and smell it. If it smells like combustion and not coolant, there is your issue @John Dirks Jr

I'll be checking the color of spark plugs too

elarm1 · Dec 13, 2015

Mine looked like poo in between 2,4 and 6,7

A5literMan · Dec 13, 2015

John Dirks Jr said:
I have Felpro gaskets (not sure the number) and I re-used the stock head bolts. The GT40 heads were milled .010 and magnafluxed crack free when installed. Thoroughly chased the block thread holes with tap and wire wheeled the bolt threads and followed all other required sealing and lubing of threads when installing. Tq to stock specs. Been running this combo for over a year prior to the V3 install with no issues. (not to suggest the V3 is related to the problem)

On mine, the temp gauge started fluctuating higher and lower but never overheated. When I checked the coolant level it was about a gallon low. Then, I found coolant drips hanging off the bottom of the gas tank cover so obviously it puked. After filling the coolant and letting it warm up to operating temp while idling everything seemed fine. Then I took it for a test drive and put the hammer down a few times. It puked again. Judging by the area of the mess, the coolant must be rapidly expanding under heavy load and blowing out of the overflow.

I filled it back up and checked for any major leaks again but found non externally. Got out the IR thermometer and while running at operating temp idling checked the temp at the intake just before the T-stat, and at the radiator directly next to the upper hose connection. At the T-stat housing 185 degrees, at the upper hose to rad connection 125 degrees. I'm hoping this indicates the coolant from the engine is not circulating into the rad (bad T-stat). I mean, how could the temp difference between those two places be 60 degrees if the coolant is flowing like it should be? There's no way the coolant temp drops 60 degrees just by flowing through the upper hose. Anyway, while testing at idle I'm assuming the heater bypass was moving just enough coolant through heater core to not let it over heat at idle but that surely wont stand up under heavy loads so thats why its puking when pushed harder.

In considering the possibility of a head gasket blown, I have a question. If everything else is good, coolant is the correct level, engine running great with no missing or any other recognizable conditions, how does the bad head gasket cause a sudden expansion of the coolant enough to make it puke? I understand over time a bad head gasket can consume the coolant through combustion and once the level gets low the engine overheats resulting in expansion. But, with full coolant and everything else good, I'm struggling to realize how a head gasket leak would cause a sudden expansion. If I'm unaware of or missing something, please school me.

Reusing the stock head bolts is a major no no! They are torque to yield and prone to stretching!! Which will cause the head to loose seal under boost. This is probably your problem. Re install with arp studs and a good t stat/cooling system and make sure there is no detonation in your tune. And then you should be fine. Otherwise this will happen again and again(blown HG)

jchav02 · Dec 13, 2015

^^^^^^^^^^
Yes never reuse factory head bolts especially with boost. Mine blew with arp head studs and 9333 gaskets. My tune is on I see .78 lambda (11.46 afr) at wot 18 degrees total timing. I've pulled my plugs no real signs, did a compression check looks good, replaced the radiator cap. You can buy a combustion leak tester at a local auto parts store. You put it on your radiator, and if it detects combustion in the cooling system it changes color. Thats what Im gonna try before I tear it down. I've been doing alot of research on this and apparently gt40's are pain to keep head gaskets on with around 10psi boost. The thin deck height of heads makes them prone to lifting under boost.

JD1964 · Dec 13, 2015

Pulled the plugs and there is a story on them. Look at the picture. #'s 3 and 4 and partially #2 look like the one on the right. All five others look like the one on the left. Normal dry carbon deposits on the rim of the left one - wetter cleaner look on the right. I'm heading out now to get a combustion in coolant checker.

Does this picture positively convince you of something specific? If so, what?

mikestang63 · Dec 13, 2015

You cannot re use TTY head bolts. i would be pulling the heads off and installing ARP studs and Felprp 9333PT1 gaskets. IMO it's only a matter of time before you blow a HG

TOOLOW91 · Dec 13, 2015

Another vote for using studs and never re using stock bolts thats a no no

JD1964 · Dec 13, 2015

I admit, in hindsight I goofed. They held up fine for over a year while NA. ARP studs and Felprp 9333PT1 gaskets are on the to do list. Time to put it down for its winter nap anyway.

JD1964 · Dec 13, 2015

Are the ARP replacement head bolts TTY? Would you avoid them and absolutely go with the ARP stud kit?

How does the stud kit perform differently than new head bolts?

JD1964 · Dec 13, 2015

Man, dont tempt me...thinking about it...

http://www.summitracing.com/parts/fms-m-6049-x306

mikestang63 · Dec 13, 2015

John Dirks Jr said:
Are the ARP replacement head bolts TTY? Would you avoid them and absolutely go with the ARP stud kit?

How does the stud kit perform differently than new head bolts?

No. The ARP bolts and studs can be reused over and over. I would never use stock TTY bolts on anything but a stock application and frankly not on any car that I cared about. Studs will withstand much more load and pressure than bolts but either are 100X better than stock bolts.

mikestang63 · Dec 13, 2015

John Dirks Jr said:
Man, dont tempt me...thinking about it...

http://www.summitracing.com/parts/fms-m-6049-x306

For about the same price, you can get a much better set of TFS or AFR heads.

JD1964 · Dec 13, 2015

How much extra HP would you guess for a good set of aluminum heads over my mildly ported GT40 irons? I like my current heads but if I'm goin in there....well...

Murphy's Law

JD1964

there is enough sticking out to grab on to

Black1987

my wife Bedazzled my input shaft

JD1964

there is enough sticking out to grab on to

jchav02

Active Member

elarm1

JD1964

there is enough sticking out to grab on to

elarm1

JD1964

there is enough sticking out to grab on to

elarm1

A5literMan

At least it is lumpy...

jchav02

Active Member

JD1964

there is enough sticking out to grab on to

mikestang63

TOOLOW91

If you're the village idiot what's that make me?

JD1964

there is enough sticking out to grab on to

JD1964

there is enough sticking out to grab on to

JD1964

there is enough sticking out to grab on to

mikestang63

mikestang63

JD1964

there is enough sticking out to grab on to

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