Thermo Time Switch

[BobH]

No problem, good luck with the remainder of your restoration

Bob

[benzwallah]

Not sure if this is a thermo switch issue, but would welcome any thoughts:

This winter, it has taken me about 10-20 cranks to start my engine.  As temperatures rose in March, it took me about 5-7 cranks.  My mechanic looked it over and said the thermo switch was no longer working, but that with warmer ambient temperatures, the car (230SL 1965) should have less trouble starting.

Yesterday, it started on the first try.  Drove it several miles and stopped for an hour.  Tried to start it, but again it cranked for about 30 times.  Weather in the 60s.  Finally, as the battery was clearly starting to lose strength, the engine barely caught, and with some delicate footwork on the accelerator, I got it to start.  Back in the garage after driving 30+minuutes to replenish the battery, I tried another re-start after turning off the engine.  It cranked again 3-4 times but caught.

I am reluctant to take the car out again.  Any thoughts or recommendations welcome.  Do I need to replace the termo switch?  The mechanic (who is terrific) implied that in warmer weather, starting it up should not be a problem since the thermo switch is only needed in colder temps.

Thanks in advance for any advice. 

[rwmastel]

Benzwallah,

As a full member, you have access to the Tech Manual.  There is great detail there about starting aid systems.  There was also a very detailed thread a few months ago that you can search for.  Lots of replies in that thread.  When searching, just limit the days age of search results to 150 (default is 9999!) and that will help you find it.

Between that thread and the Tech Manual, you can educate yourself quite a bit.  That may be an understatement.  You can do some diagnosis yourself, or some repairs yourself, or just use your new found knowledge and tell the mechanic what to do.  It will impress him/her!

[Figoulu]

No problem, good luck with the remainder of your restoration

Bob

I finally went for “normal” connection as the iso connector hasn’t enough space with the curved hose…

[BobH]

Not sure if this is a thermo switch issue, but would welcome any thoughts:

This winter, it has taken me about 10-20 cranks to start my engine.  As temperatures rose in March, it took me about 5-7 cranks.  My mechanic looked it over and said the thermo switch was no longer working, but that with warmer ambient temperatures, the car (230SL 1965) should have less trouble starting.

Yesterday, it started on the first try.  Drove it several miles and stopped for an hour.  Tried to start it, but again it cranked for about 30 times.  Weather in the 60s.  Finally, as the battery was clearly starting to lose strength, the engine barely caught, and with some delicate footwork on the accelerator, I got it to start.  Back in the garage after driving 30+minuutes to replenish the battery, I tried another re-start after turning off the engine.  It cranked again 3-4 times but caught.

I am reluctant to take the car out again.  Any thoughts or recommendations welcome.  Do I need to replace the termo switch?  The mechanic (who is terrific) implied that in warmer weather, starting it up should not be a problem since the thermo switch is only needed in colder temps.

Thanks in advance for any advice.

Hello, there are some excellent write up's on here and in the tech manual, but it can be a bit overwhelming getting your head around how the cold start components work together.  Your mechanic says he suspects the thermo time switch (TTS) may be faulty, but has he diagnosed it?  there are several components involved, the TTS, the cold start relay, the cold start valve and some other bits.  The quickest way to rule out if the TTS is faulty is to temporarily apply an earth/ground wire directly to terminal W (where the pink wire is connected) and then crank the engine.  If it starts easily then the TTS may be at fault, but you'll then need to test it fully to make sure before you splash out on a replacement.  There are descriptions on how to test it on the various posts and in the tech manual.  In the meantime you can use the earth wire to start the car if that works, until you sort a permanent fix.  Some owners have wired a push button, as a manual "choke" to bypass the TTS.  If the earth wire doesn't work, there may be a problem with the relay or the cold start valve, (the solenoid or the spray nozzles), or the wiring in between.  Please let us know how you get on
Good luck