C4 Failure! Where to look next?
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C4 Failure! Where to look next?
So I have been working on my vette for a few weeks. So far I have replaced-
- MAF
- MAF relays
- Fan Relay
- Vac Lines
- 160 Thermostat
- Fuel injectors
- Air filter
And now my car runs GREAT! Until that is it heats up to 220 and then it all begins. It starts to bog when you give it full throttle and the temps continues to rise and it gets worse as is gets hotter. I turn it off at 250. After I turn it off I hear the coolant boiling but it doesnt spill.
What should I look at now? I have no engine codes present and am at a lose. HMMMMM
- MAF
- MAF relays
- Fan Relay
- Vac Lines
- 160 Thermostat
- Fuel injectors
- Air filter
And now my car runs GREAT! Until that is it heats up to 220 and then it all begins. It starts to bog when you give it full throttle and the temps continues to rise and it gets worse as is gets hotter. I turn it off at 250. After I turn it off I hear the coolant boiling but it doesnt spill.
What should I look at now? I have no engine codes present and am at a lose. HMMMMM
Pro
Joined: May 2006
Posts: 637
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Did you actually look at the state of the oil and the coolant?
Is perhaps oil mixing with coolant?
If you hear the coolant boiling, that is not a good thing.
I would check the oil and the coolant for contamination.
And how does it look like between the radiators, any debris there that can block airflow like leaves and other crap?
A thermostat stuck in closed position (even a new one could be bad) doesn´t let the coolant flow through the radiator, result is coolant getting warmer since it doesn´t get cooled by the airflow through the rad.
Let the engine get up to temp or above, then feel if the hose (upper) gets really warm too (or not, in that case it´s the thermostat).
It can also be an air bubble in the coolant system that can cause trouble; burp it.
How is the waterpump itself?
Even a fan that works doesn´t do anything but cool down coolant that hasn´t run through the engine when the thermostat is stuck closed.
Some stuff to check out, and all free of charge or parts (that is... the checks of course).
Is perhaps oil mixing with coolant?
If you hear the coolant boiling, that is not a good thing.
I would check the oil and the coolant for contamination.
And how does it look like between the radiators, any debris there that can block airflow like leaves and other crap?
A thermostat stuck in closed position (even a new one could be bad) doesn´t let the coolant flow through the radiator, result is coolant getting warmer since it doesn´t get cooled by the airflow through the rad.
Let the engine get up to temp or above, then feel if the hose (upper) gets really warm too (or not, in that case it´s the thermostat).
It can also be an air bubble in the coolant system that can cause trouble; burp it.
How is the waterpump itself?
Even a fan that works doesn´t do anything but cool down coolant that hasn´t run through the engine when the thermostat is stuck closed.
Some stuff to check out, and all free of charge or parts (that is... the checks of course).
Thread Starter
Advanced
Joined: May 2010
Posts: 85
Likes: 0
Did you actually look at the state of the oil and the coolant?
Is perhaps oil mixing with coolant?
If you hear the coolant boiling, that is not a good thing.
I would check the oil and the coolant for contamination.
And how does it look like between the radiators, any debris there that can block airflow like leaves and other crap?
A thermostat stuck in closed position (even a new one could be bad) doesn´t let the coolant flow through the radiator, result is coolant getting warmer since it doesn´t get cooled by the airflow through the rad.
Let the engine get up to temp or above, then feel if the hose (upper) gets really warm too (or not, in that case it´s the thermostat).
It can also be an air bubble in the coolant system that can cause trouble; burp it.
How is the waterpump itself?
Even a fan that works doesn´t do anything but cool down coolant that hasn´t run through the engine when the thermostat is stuck closed.
Some stuff to check out, and all free of charge or parts (that is... the checks of course).
Is perhaps oil mixing with coolant?
If you hear the coolant boiling, that is not a good thing.
I would check the oil and the coolant for contamination.
And how does it look like between the radiators, any debris there that can block airflow like leaves and other crap?
A thermostat stuck in closed position (even a new one could be bad) doesn´t let the coolant flow through the radiator, result is coolant getting warmer since it doesn´t get cooled by the airflow through the rad.
Let the engine get up to temp or above, then feel if the hose (upper) gets really warm too (or not, in that case it´s the thermostat).
It can also be an air bubble in the coolant system that can cause trouble; burp it.
How is the waterpump itself?
Even a fan that works doesn´t do anything but cool down coolant that hasn´t run through the engine when the thermostat is stuck closed.
Some stuff to check out, and all free of charge or parts (that is... the checks of course).
Its a start. Thanks for the info!
Why would the car begin to bog out around 210 and above? Is it just because its getting hot or is there another explanation??
Pro
Joined: May 2006
Posts: 637
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Just thinking out loud and the other way around now, but could you have a clogged cat.
Making the engine warmer than normal, not getting rid of the exhaust gases fast enough.
And making the engine bog out (does this happen at a certain RPM, like 2500-3000?).
Just a thought...
Making the engine warmer than normal, not getting rid of the exhaust gases fast enough.
And making the engine bog out (does this happen at a certain RPM, like 2500-3000?).
Just a thought...
Thread Starter
Advanced
Joined: May 2010
Posts: 85
Likes: 0
Just thinking out loud and the other way around now, but could you have a clogged cat.
Making the engine warmer than normal, not getting rid of the exhaust gases fast enough.
And making the engine bog out (does this happen at a certain RPM, like 2500-3000?).
Just a thought...
Making the engine warmer than normal, not getting rid of the exhaust gases fast enough.
And making the engine bog out (does this happen at a certain RPM, like 2500-3000?).
Just a thought...
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Le Mans Master
Joined: Nov 2009
Posts: 6,882
Likes: 234
From: Bangkok, Thailand
It could also be a stuck thermostat. Remember that a t-stat is a "regulator". Its job is to allow hot water from the engine to move into the raditor, and then close. The water in the radiator then sheds heat, while the cooler water that just came from the radiator and moved into the engine pulls heat from the engine. As the engine water heats, the t-stat opens, and the water changes places again.
If the stat is stuck open, the water doesn't get enough time in the radiator to shed heat and you end up overheating.
If the stat is stuck open, the water doesn't get enough time in the radiator to shed heat and you end up overheating.
Race Director
Joined: Jun 2009
Posts: 10,428
Likes: 9
From: Southside of Western Norte Americano State of Confusion, ColoFornia
St. Jude '13
Ok.. time for a little methodology here.. Fix the heating issue first.. the bog is more than likely heat related.. as the temp gauge may not be accurate and the engine may be hotter than 220.. dont let yourself get distracted by multiple issues.
If the car runs good until it gets to 220 then it probably isnt a clogged converter. try a few things first.. put the nose of the car up and make sure the coolant level is full in the radiator not the coolant tank. (lifting the nose will help eliminate airbubbles in the block)
you can also "pack the cooling system" with the nose on ramps, with the radiator cap off warm the engine up when the T-stat opens (you will see the water moving in the rad).. increase the engine rpms to say 1500 -2000 you will need help to do this as you need to add it at the higher rpms and cap it. this will pull the coolant level down in the radiator, now add more till its full..and cap it. it will push any excess out into the coolant recovery bottle when it cools off.
Cleaning the crap out form between the radiator and AC condenser is a good move also. take care of the basics and you may just solve the problem.
Verify that your fans are coming on..(hey it sounds dumb to say.. but it has to be done)
Keep us posted.
If the car runs good until it gets to 220 then it probably isnt a clogged converter. try a few things first.. put the nose of the car up and make sure the coolant level is full in the radiator not the coolant tank. (lifting the nose will help eliminate airbubbles in the block)
you can also "pack the cooling system" with the nose on ramps, with the radiator cap off warm the engine up when the T-stat opens (you will see the water moving in the rad).. increase the engine rpms to say 1500 -2000 you will need help to do this as you need to add it at the higher rpms and cap it. this will pull the coolant level down in the radiator, now add more till its full..and cap it. it will push any excess out into the coolant recovery bottle when it cools off.
Cleaning the crap out form between the radiator and AC condenser is a good move also. take care of the basics and you may just solve the problem.
Verify that your fans are coming on..(hey it sounds dumb to say.. but it has to be done)
Keep us posted.
Last edited by Bondami; Jun 7, 2010 at 01:52 PM.
Le Mans Master
Joined: Mar 2004
Posts: 8,700
Likes: 298
From: Ft. Lauderdale Fl
A thermostat stuck in closed position (even a new one could be bad) doesn´t let the coolant flow through the radiator, result is coolant getting warmer since it doesn´t get cooled by the airflow through the rad.
Happened to me several years ago.
Did you mix 50/50 anti-freeze and distilled water? Don't think it should boil with above mixture.
Happened to me several years ago.
Did you mix 50/50 anti-freeze and distilled water? Don't think it should boil with above mixture.
Pro
Joined: Jun 2001
Posts: 520
Likes: 6
From: Elverson PA
Thermostat is stuck or too much air in the system. Maybe an air bubble stuck on the thermostat. I always drill a hole in it if there isn't one in there to keep air from forming a bubble under there. TPIS says to always enlarge the hole a little anyway.
You just changed your coolant? Did this happen before the change?
You just changed your coolant? Did this happen before the change?
Le Mans Master
Joined: Feb 2000
Posts: 9,715
Likes: 27
From: Kempner Texas
Continuing to throw parts at your problem doesn't seem to be paying off, so it's time to diagnose the cause.
Sure, you can install a new stat after drilling two 1/16" holes in it to ease bleeding air from your coolng system. That's inexpensive, easy to do and may cure the over-heating problem.
You should also connect a scanner to the engine to see if there's a sensor operating out of range. A sensor like the Intake Air Temperature sensor or the 02 sensor, etc. As it is now, you're more like "guessing" at the cause.
Jake
My son, Ryan M. Cameron, graduated from West Point on 22 May 2010! He was commissioned as a 2nd Lieutenant and I pinned on his first pair of "Butter Bars" PROUDEST DAY OF MY LIFE!!
Sure, you can install a new stat after drilling two 1/16" holes in it to ease bleeding air from your coolng system. That's inexpensive, easy to do and may cure the over-heating problem.
You should also connect a scanner to the engine to see if there's a sensor operating out of range. A sensor like the Intake Air Temperature sensor or the 02 sensor, etc. As it is now, you're more like "guessing" at the cause.
Jake
My son, Ryan M. Cameron, graduated from West Point on 22 May 2010! He was commissioned as a 2nd Lieutenant and I pinned on his first pair of "Butter Bars" PROUDEST DAY OF MY LIFE!!
Burning Brakes
Joined: Oct 2009
Posts: 773
Likes: 2
From: Minneapolis MN
I agree with all.Start with overheating issue first-possible causes(could be fan not coming on,thermostat,air in system,debris in front of radiator,bad EGR valve,head gasket).A clogged cat will cause sluggish performance & a vacuum leak because the hot gas is going into intake from opening intake valves.The 2 problems may be related.I think a sensor is getting hot & causing the running issues(ignition module,coil,TPS,or even fuel injector).Throwing parts at things is ok if you have the $ but its best to start with the overheating issue then work from there.Keep us updated
Cruising
Joined: Feb 2000
Posts: 14
Likes: 0
From: BLOOMINGTON Il
I also agree with dealing with the overheating first. I have heard of folks actually removing the radiator and finding all sorts of debris in there that contributed to the cooling issues. Also the fan relay can be a problem, it should kick on as the temp approaches 230 I think and immediately start cooling things down.
Le Mans Master
Joined: Oct 1999
Posts: 6,366
Likes: 34
If you think you have a coolant pressure issue (blown head gasket) you can run the car with the radiator cap off. Let it heat up to temp and look for bubbles in the coolant.
You can pull the radiator fairly easy, wash it out, and get the debris out of it and you may be suprised at how much better it works. I actually layed mine upright on my lawn, and let it drop forward and a ton of sand came out of it. this was after washing it out. I was running around 10 degrees cooler after.
Does it run upto red line fine before you get to 220?
also I would double check the timming on it.
You can pull the radiator fairly easy, wash it out, and get the debris out of it and you may be suprised at how much better it works. I actually layed mine upright on my lawn, and let it drop forward and a ton of sand came out of it. this was after washing it out. I was running around 10 degrees cooler after.
Does it run upto red line fine before you get to 220?
also I would double check the timming on it.
Last edited by bill mcdonald; Jun 8, 2010 at 04:38 PM.
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Ok so the problem is all the time not just when hot. Here is a vid......
The first pull you see is a slow pull
the next 2 are full pulls not letting off
last pull is another slow pull.
It performs well as should during the slow pulls but when I mash it to the floor it says grrrrrr
The first pull you see is a slow pull
the next 2 are full pulls not letting off
last pull is another slow pull.
It performs well as should during the slow pulls but when I mash it to the floor it says grrrrrr
Le Mans Master
Joined: Oct 1999
Posts: 6,366
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Listening to that sounds like something is not right. A rattle in the exhuast and when you let off it sounded like it let off some pressure. Maybe it is just the way it comes across in the recording.
I am guessing clogged cats.
When mine went, they just went all out. Couldn't go over 2K rpms when driving.
I am guessing clogged cats.
When mine went, they just went all out. Couldn't go over 2K rpms when driving.
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