Problems after Opti/H2O swap
Thread Starter
Advanced
Joined: Feb 2011
Posts: 82
Likes: 1
Problems after Opti/H2O swap
I changed out the opti spark and water pump over the last week because I got the opti wet during a wash a few weeks ago and the car was performing very poorly. When everything was back in place, the car started fine and idled and revved to around 3k just great. So I filled it with about 2 gallons of 50/50 coolant and distilled water up to the neck of the reservoir cap. When I took it out for about 2 or 3 miles to get it to operating temperature I noticed 3 problems:
I think my biggest/first concern is the stuttering at 4k rpms. Any ideas?
As always, thanks for the expert advice. I'm certainly learning a lot doing all of this stuff on my own. I used to be happy that I changed my own oil and rotated the tires. Doing this job on my own may have saved me $500.
- The car seems to stutter (like a subtle governor) around 4k rpms, runs great at lower rpms though
- The analog temp gauge on the cluster is pegged to the top (bottom?). I assume this is a problem with the coolant temperature sensor? I put a new one in as I snapped the old one off the water pump during removal. I'll have to check connections on it too, perhaps the plug or sensor itself is not seated properly. The digital gauge seemed to work though, the temps got to 221 and both fans are working. Would this be caused by the CTS or something else?
- When I got back to the garage a boiling / gurgling sound was heard in the coolant system. I assume this is because I didn't burp the system properly so I will try to burp it and see if that solves the problem. Or could it be something else? I didn't see any leaks or steam and as I said the fans were on and the temps didn't go above 221. What is the proper procedure to burp it? I think there are 2 places to do it? I just let the engine run for a few minutes with the cap off until the bubbles stopped.
I think my biggest/first concern is the stuttering at 4k rpms. Any ideas?
As always, thanks for the expert advice. I'm certainly learning a lot doing all of this stuff on my own. I used to be happy that I changed my own oil and rotated the tires. Doing this job on my own may have saved me $500.
Race Director
Joined: Sep 2001
Posts: 14,676
Likes: 751
From: NEwhere Ohio
I changed out the opti spark and water pump over the last week because I got the opti wet during a wash a few weeks ago and the car was performing very poorly. When everything was back in place, the car started fine and idled and revved to around 3k just great. So I filled it with about 2 gallons of 50/50 coolant and distilled water up to the neck of the reservoir cap. When I took it out for about 2 or 3 miles to get it to operating temperature I noticed 3 problems:
I think my biggest/first concern is the stuttering at 4k rpms. Any ideas?
As always, thanks for the expert advice. I'm certainly learning a lot doing all of this stuff on my own. I used to be happy that I changed my own oil and rotated the tires. Doing this job on my own may have saved me $500.
- The car seems to stutter (like a subtle governor) around 4k rpms, runs great at lower rpms though
- The analog temp gauge on the cluster is pegged to the top (bottom?). I assume this is a problem with the coolant temperature sensor? I put a new one in as I snapped the old one off the water pump during removal. I'll have to check connections on it too, perhaps the plug or sensor itself is not seated properly. The digital gauge seemed to work though, the temps got to 221 and both fans are working. Would this be caused by the CTS or something else?
- When I got back to the garage a boiling / gurgling sound was heard in the coolant system. I assume this is because I didn't burp the system properly so I will try to burp it and see if that solves the problem. Or could it be something else? I didn't see any leaks or steam and as I said the fans were on and the temps didn't go above 221. What is the proper procedure to burp it? I think there are 2 places to do it? I just let the engine run for a few minutes with the cap off until the bubbles stopped.
I think my biggest/first concern is the stuttering at 4k rpms. Any ideas?
As always, thanks for the expert advice. I'm certainly learning a lot doing all of this stuff on my own. I used to be happy that I changed my own oil and rotated the tires. Doing this job on my own may have saved me $500.
Anything other than ac delco oem new old stock or delphi ...chances are high that it wont work right (see my recent post that starts with the title rant)
Even ac delco 'rest assured' remanufactured optispark can be defective as I discovered they recycle the mitsubishi sensor vs. replace it. meanwhile they do a great job replcing bearing/seals. doesnt do any good if the heart of the unit (mitsubishi sensor) is broke and the reason why the core was taken out of service..
Opti is almost impossible to install wrong.
Id check plugs/wires ...
Good luck
Ive had the misfortune of replacing opti with a remanufactured unit only to have to tear it down again due to it being defective.
Last edited by dizwiz24; Oct 10, 2013 at 07:42 PM.
Melting Slicks
Joined: Aug 2008
Posts: 2,082
Likes: 50
From: Palmdale CA
I changed out the opti spark and water pump over the last week because I got the opti wet during a wash a few weeks ago and the car was performing very poorly. When everything was back in place, the car started fine and idled and revved to around 3k just great. So I filled it with about 2 gallons of 50/50 coolant and distilled water up to the neck of the reservoir cap. When I took it out for about 2 or 3 miles to get it to operating temperature I noticed 3 problems:
I think my biggest/first concern is the stuttering at 4k rpms. Any ideas?
As always, thanks for the expert advice. I'm certainly learning a lot doing all of this stuff on my own. I used to be happy that I changed my own oil and rotated the tires. Doing this job on my own may have saved me $500.
- The car seems to stutter (like a subtle governor) around 4k rpms, runs great at lower rpms though
- The analog temp gauge on the cluster is pegged to the top (bottom?). I assume this is a problem with the coolant temperature sensor? I put a new one in as I snapped the old one off the water pump during removal. I'll have to check connections on it too, perhaps the plug or sensor itself is not seated properly. The digital gauge seemed to work though, the temps got to 221 and both fans are working. Would this be caused by the CTS or something else?
- When I got back to the garage a boiling / gurgling sound was heard in the coolant system. I assume this is because I didn't burp the system properly so I will try to burp it and see if that solves the problem. Or could it be something else? I didn't see any leaks or steam and as I said the fans were on and the temps didn't go above 221. What is the proper procedure to burp it? I think there are 2 places to do it? I just let the engine run for a few minutes with the cap off until the bubbles stopped.
I think my biggest/first concern is the stuttering at 4k rpms. Any ideas?
As always, thanks for the expert advice. I'm certainly learning a lot doing all of this stuff on my own. I used to be happy that I changed my own oil and rotated the tires. Doing this job on my own may have saved me $500.
[B1] did you mix 50/50 coolent with water?
[B2] the Analog gauge measures your R/H cylinder Head temp with a probe located between Cyl's 6 & 8 on the head it-self.. Not on the Block.
[B3] This was caused by either; Antifreeze mixed below 265°f boil temp, or; air in the system, or both.
Your car was not ready to be driven! hopefully your heads survived the ordeal.. time will tell.
Drifting
Joined: Mar 2012
Posts: 1,492
Likes: 61
From: New Jersey
I not sure but I think that the coolant temp. sensor on the water pump is involved in engine operation - that is, the engine will not go into closed loop if that sensor is not operating. That may account for the problems you are having above 4k rpm (otherwise it could be an opti problem - some are bad out of the box). Check and make sure that is working before anything else. 
Melting Slicks
Joined: Aug 2008
Posts: 2,082
Likes: 50
From: Palmdale CA
Yes it does, and this is used to remove most air, up to the thermostat level (only) Keep in mind there are other areas for air to [Hang out] such as in the heads, radiator, heater core, and hose's. The LT engines have a small 10mm hose that is tapped into both heads, and at the top of the radiator in order to facilitate trapped air removal, by sending the air on up to the surge tank were it is allowed to escape into the recovery tank.
When the engine cools it draws coolent from the recovery system.
When the engine cools it draws coolent from the recovery system.
Melting Slicks
Joined: Jan 2009
Posts: 3,181
Likes: 286
From: Puyallup Washington
My 1992 has 2 air bleed screws. One is at the front top and is obvious. The other is a little lower and hidden. When I changed the coolant in mine 2 years ago I let the air out using these two air bleed screws and had no problems afterwards. Just make sure to keep the opti dry while bleeding the air out.
Thread Starter
Advanced
Joined: Feb 2011
Posts: 82
Likes: 1
Wht brand opti did you use ?
Anything other than ac delco oem new old stock or delphi ...chances are high that it wont work right (see my recent post that starts with the title rant)
Even ac delco 'rest assured' remanufactured optispark can be defective as I discovered they recycle the mitsubishi sensor vs. replace it. meanwhile they do a great job replcing bearing/seals. doesnt do any good if the heart of the unit (mitsubishi sensor) is broke and the reason why the core was taken out of service..
Opti is almost impossible to install wrong.
Id check plugs/wires ...
Good luck
Ive had the misfortune of replacing opti with a remanufactured unit only to have to tear it down again due to it being defective.
Anything other than ac delco oem new old stock or delphi ...chances are high that it wont work right (see my recent post that starts with the title rant)
Even ac delco 'rest assured' remanufactured optispark can be defective as I discovered they recycle the mitsubishi sensor vs. replace it. meanwhile they do a great job replcing bearing/seals. doesnt do any good if the heart of the unit (mitsubishi sensor) is broke and the reason why the core was taken out of service..
Opti is almost impossible to install wrong.
Id check plugs/wires ...
Good luck
Ive had the misfortune of replacing opti with a remanufactured unit only to have to tear it down again due to it being defective.
Corvette Stories
The Best of Corvette for Corvette Enthusiasts
Top 10 Most Expensive Corvettes Ever Sold on Bring A Trailer
Brett Foote
10 Things Every Corvette Owner Needs (2026 Edition)
Michael S. Palmer
8 Most "Only Corvette Owners Understand" Quirks and Problems
Pouria Savadkouei
10 Reasons the C6 Z06 is Still A Performance Benchmark After 20 Years
Joe Kucinski
How Much Horsepower Every Corvette Engine "LOST" in 1972
Joe Kucinski
Top 10 DOs and DON'Ts for Protecting Your Convertible Top!
Michael S. Palmer
Top 10 Most Explosive Corvettes Ever Made: Power-to-Weight Ratio Ranked!
Joe Kucinski
150 hp to 1,250 hp: Every Corvette Generation Compared by the Specs That Matter
Joe Kucinski
8 Coolest Corvette Pace Cars (and Replicas) of All Time
Verdad Gallardo
Thread Starter
Advanced
Joined: Feb 2011
Posts: 82
Likes: 1
My 1992 has 2 air bleed screws. One is at the front top and is obvious. The other is a little lower and hidden. When I changed the coolant in mine 2 years ago I let the air out using these two air bleed screws and had no problems afterwards. Just make sure to keep the opti dry while bleeding the air out.
Thread Starter
Advanced
Joined: Feb 2011
Posts: 82
Likes: 1
Last night I opened the rad cap and the water level was noticeably lower, so I added close to a quart. The overflow tank was also lower. I opened the bleed screw on top of the thermostat and a bit of air was released then a steady stream of water.
So I closed it and ran the car to 221. Again, both fans came on and the temp dropped to 217 and stayed there (bouncing around a bit). There wasn't "hot" air coming out of the vents, but warm air did eventually come out. I turned of the car and the boiling sound was again very loud, so I didn't fix it. I'll check the fluid levels tonight.
I wondered if I didn't have the rad cap on properly or the cap to the overflow does have a good seal. Could that be it or am I just not bleeding it properly?
So I closed it and ran the car to 221. Again, both fans came on and the temp dropped to 217 and stayed there (bouncing around a bit). There wasn't "hot" air coming out of the vents, but warm air did eventually come out. I turned of the car and the boiling sound was again very loud, so I didn't fix it. I'll check the fluid levels tonight.
I wondered if I didn't have the rad cap on properly or the cap to the overflow does have a good seal. Could that be it or am I just not bleeding it properly?
Race Director
Joined: Sep 2001
Posts: 14,676
Likes: 751
From: NEwhere Ohio
Yes, those ones have had issues.
The problem is msd will simply give you a new one. they do not reimburse you for your time.
Its a crapshoot if you will get an msd that works.
Optispark is not a maintenance item that should need replaced every 2nd oil change.
The early units (without venting) are easily fixed and becomre reliable when adding venting
The problem is msd will simply give you a new one. they do not reimburse you for your time.
Its a crapshoot if you will get an msd that works.
Optispark is not a maintenance item that should need replaced every 2nd oil change.
The early units (without venting) are easily fixed and becomre reliable when adding venting
Melting Slicks
Joined: Aug 2008
Posts: 2,082
Likes: 50
From: Palmdale CA
I asked you in an earlier post, did you mix 50/50 Antifreeze with water?
Water boils at 250°f with a 15psig (realative to vacuum) or (two atmos) then add antifreeze [50/50] and this number will increase to about 265°f now if your system fails to pressurize this number drops down (1 atmos) sea level= 212°f not sure what this number is W/ 50/50 antifreeze ?
Sooo if your mix is wrong, or the cooling system fails to pressurize this could cause pre-mature boiling.
On the other hand air in the system could cause problems as well!
Radiator caps are cheap. I would change this without question!
A simple test I allways do is squeeze a radiator hose with the engine cold, and then again when it's at operating temperature, it should get hard when the system pressurizes.
Water boils at 250°f with a 15psig (realative to vacuum) or (two atmos) then add antifreeze [50/50] and this number will increase to about 265°f now if your system fails to pressurize this number drops down (1 atmos) sea level= 212°f not sure what this number is W/ 50/50 antifreeze ?
Sooo if your mix is wrong, or the cooling system fails to pressurize this could cause pre-mature boiling.
On the other hand air in the system could cause problems as well!
Radiator caps are cheap. I would change this without question!
A simple test I allways do is squeeze a radiator hose with the engine cold, and then again when it's at operating temperature, it should get hard when the system pressurizes.
Thread Starter
Advanced
Joined: Feb 2011
Posts: 82
Likes: 1
I asked you in an earlier post, did you mix 50/50 Antifreeze with water?
Water boils at 250°f with a 15psig (realative to vacuum) or (two atmos) then add antifreeze [50/50] and this number will increase to about 265°f now if your system fails to pressurize this number drops down (1 atmos) sea level= 212°f not sure what this number is W/ 50/50 antifreeze ?
Sooo if your mix is wrong, or the cooling system fails to pressurize this could cause pre-mature boiling.
On the other hand air in the system could cause problems as well!
Radiator caps are cheap. I would change this without question!
A simple test I allways do is squeeze a radiator hose with the engine cold, and then again when it's at operating temperature, it should get hard when the system pressurizes.
Water boils at 250°f with a 15psig (realative to vacuum) or (two atmos) then add antifreeze [50/50] and this number will increase to about 265°f now if your system fails to pressurize this number drops down (1 atmos) sea level= 212°f not sure what this number is W/ 50/50 antifreeze ?
Sooo if your mix is wrong, or the cooling system fails to pressurize this could cause pre-mature boiling.
On the other hand air in the system could cause problems as well!
Radiator caps are cheap. I would change this without question!
A simple test I allways do is squeeze a radiator hose with the engine cold, and then again when it's at operating temperature, it should get hard when the system pressurizes.
Thread Starter
Advanced
Joined: Feb 2011
Posts: 82
Likes: 1
An update:
The system still gurgles when it gets above 200. The hoses have plenty of give and easily squeeze when the system is cool, however at operating temperature, the hoses become firm. So, the system is pressurizing. Should I remove some of the liquid and add more coolant? Is it safe to drive in this condition?
Also, regarding the temperature gauges. It seems they (the digital and analog gauges) are not in sync. They both read different temps and the analog gauge is not initially pegged. However, when the digital temp reads about 190 or so, that is when the analog gauge reaches the top and pegs out. What could cause that?
Thanks for any ideas or help-
The system still gurgles when it gets above 200. The hoses have plenty of give and easily squeeze when the system is cool, however at operating temperature, the hoses become firm. So, the system is pressurizing. Should I remove some of the liquid and add more coolant? Is it safe to drive in this condition?
Also, regarding the temperature gauges. It seems they (the digital and analog gauges) are not in sync. They both read different temps and the analog gauge is not initially pegged. However, when the digital temp reads about 190 or so, that is when the analog gauge reaches the top and pegs out. What could cause that?
Thanks for any ideas or help-
Race Director
Joined: Apr 2009
Posts: 19,294
Likes: 2,754
From: Charlotte NC
EDIT
I have encountered the SMALL hose that attaches to the top of your radiator....that "T"'s off and goes to the expansion tank and then the front of the engine( on some year models) and will also go the the passenger rear on other year models.... is plugged.
When the engine is COLD....remove your radiator cap...crank the engine and with your finger...reach down inside the expansion tank and feel if you can feel coolant mix coming into the tank from the upper radiator SMALL hose. IF you don't...your radiator can have an air pocket in it due to the special hose assembly is plugged....and air can NOT get out.
Also...on another note...with a flash light...look from the right side of the radiator assembly and look in front of the left cooling fan. usually there is a ton of crap in front of where the fan pulls air through. If there is...you have to blow it out or your fan will do no good due to the front face of the radiator is blocked.
DUB
I have encountered the SMALL hose that attaches to the top of your radiator....that "T"'s off and goes to the expansion tank and then the front of the engine( on some year models) and will also go the the passenger rear on other year models.... is plugged.
When the engine is COLD....remove your radiator cap...crank the engine and with your finger...reach down inside the expansion tank and feel if you can feel coolant mix coming into the tank from the upper radiator SMALL hose. IF you don't...your radiator can have an air pocket in it due to the special hose assembly is plugged....and air can NOT get out.
Also...on another note...with a flash light...look from the right side of the radiator assembly and look in front of the left cooling fan. usually there is a ton of crap in front of where the fan pulls air through. If there is...you have to blow it out or your fan will do no good due to the front face of the radiator is blocked.
DUB
Last edited by DUB; Oct 14, 2013 at 05:42 PM. Reason: Add info.
Thread Starter
Advanced
Joined: Feb 2011
Posts: 82
Likes: 1
I think I finally found the issue. It was a rookie mistake, after all I really don't have much experience doing this stuff. I used to be happy that I could change my own oil, rotate tires or change brake pads. I was actually wondering about this gear that I saw, but I thought it rested on top of, below or beside the other one. Yes, I neglected to remove the sleeve that connects the water pump gear to the timing chain gear. So, nothing was moving the pump or the water.
I hope this helps someone else out in the future. It should only cost me a few gaskets and a couple hours of time.
Would this missing part explain the difference in temps between the digital and analog temperature gauges though? It doesn't seem like it would.
I'll try to get a pick up here so others can see what I am talking about if it helps make sense to someone.
I hope this helps someone else out in the future. It should only cost me a few gaskets and a couple hours of time.
Would this missing part explain the difference in temps between the digital and analog temperature gauges though? It doesn't seem like it would.
I'll try to get a pick up here so others can see what I am talking about if it helps make sense to someone.
Last edited by jadiff; Oct 17, 2013 at 04:33 PM. Reason: added pics