Topic: Wont start when hot...
in Forum: C3 Engines
Already a Member?
Click Here to Login
Not yet a Member?
Click Here to Register for Free!
Lifetime MemberElma, WA - USA
Joined: 6/25/2007
Posts: 692
Vette(s): Red 1973 Convertible.
L-48 Auto
#'s matching
Red 1970 LT-1
Convertible
#'s matching
One thing I have discovered is on a hot day, above 85 degrees or so the LT-1 runs about 10-15 degrees warmer than normal at typical freeway speeds.
The problem is when I stop after coming off the freeway and its up around 200 degrees it wont start.
Nothing, just a small click.
After it cools, maybe 10-20 minutes it starts right up.
So is it a radiator issue or a starter issue?
I dont know if this is the starter expanding under the heat or a vapor lock. (Never had a vapor lock before so I have no idea what that deal is.)
Any help would be of great assistance here.
Thanks in advance....
The problem is when I stop after coming off the freeway and its up around 200 degrees it wont start.
Nothing, just a small click.
After it cools, maybe 10-20 minutes it starts right up.
So is it a radiator issue or a starter issue?
I dont know if this is the starter expanding under the heat or a vapor lock. (Never had a vapor lock before so I have no idea what that deal is.)
Any help would be of great assistance here.
Thanks in advance....
SPONSOR AD:: (Our Sponsors help support C3VR)
Former Member
Send PM
Oak Creek, WI - USA
Joined: 5/21/2008
Posts: 1965
Vette(s): 1981 Great White Shark. Red Interior, 350/190 hp. PS, PB (SS), A/C CC, T-Tops. Served three years in Active Duty Army, then Retired Air Force after 34 years! Badger State Vettes Car Club. 175,000 Original miles!! Now own a 1998 C-5!
Sounds like Vapor lock to me !!
What thermostat do you have in it? 180' or 195'
(click to see a larger image)
"It Takes A Little Longer To Do It Right"
"It Takes A Lot Longer To Do It Again"
If the engine's operating temp is up over 200 it isn't going to matter what temp the thermostat is.
But based on your description I'd say it's the starter. If it were vapor lock it would turnover as normal but just not fire. You may need to put a thermal barrier between the header (or exhaust pipe) and the starter or go with a mini-starter that gets more airspace between it and the header (or exhaust pipe).
I solved the vapor lock issue on "The Toy" by putting a Mr. Gasket plate kit between the intake and the carb. Before I did that the carb was so hot you couldn't touch it which was boiling the fuel out of the bowl. After putting in as many plates as I could (alternating gasket and aluminum ones) the carb stays a lot cooler (as does my temper!). The only modification I had to make was to fabricate a longer bar for the choke linkage.
I solved the vapor lock issue on "The Toy" by putting a Mr. Gasket plate kit between the intake and the carb. Before I did that the carb was so hot you couldn't touch it which was boiling the fuel out of the bowl. After putting in as many plates as I could (alternating gasket and aluminum ones) the carb stays a lot cooler (as does my temper!). The only modification I had to make was to fabricate a longer bar for the choke linkage.
Jim Olson 
"The Toys"...!!! Save the Wave! 
Lifetime MemberHOWELL, NJ - USA
Joined: 5/18/2004
Posts: 6812
Vette(s): 1979, Targa Blue (72 Color), Pace Car rear spoiler, L88 hood, Dark blue factory interior, 525HP 406, HD 700R4, 370 gears,Steeroids, composite rear spring, TT IIs wrapped in T/A Radials.
Definitely sounds like the starter solenoid overheating. You could try an insulator:
LukesVette 2009-07-06 13:31:17
LukesVette Homepage
Veteran of Operation Iraqi Freedom
101st Airborne(AirAssault!)
God Bless America
Support Our Troops 
John, does it have headers? If so look to see how close they might be to the starter. The starter could be getting too hot and a heat wrap or shield might be in your future. OR as mentioned above a mini starter might be a good thing also.Aaron1976 2009-07-06 13:21:37
Aaron 
CLICK HERE to enlarge picture
Lifetime MemberElma, WA - USA
Joined: 6/25/2007
Posts: 692
Vette(s): Red 1973 Convertible.
L-48 Auto
#'s matching
Red 1970 LT-1
Convertible
#'s matching
Thats the kind of help I was a lookin for!
Thanks a bunch.
I didnt know if a vapor lock would allow the motor to turn over which it sounds like it does.
I will get one of those wraps and like rick says "case closed"!
T-Mans70,73 2009-07-06 17:04:45
Thanks a bunch.
I didnt know if a vapor lock would allow the motor to turn over which it sounds like it does.
I will get one of those wraps and like rick says "case closed"!
in Forum: C3 Engines
SPONSOR AD: (Our Sponsors help support C3VR)