How do solenoids fail?

[curlesw]

I am having intermittent starting issues. When I turn the key the dashboard lights come on but the car will not start. After a few tries the car will finally start. My previous question resulted in “clean the contacts”…I did that but the problem still exists.

So, maybe I did not clean the contacts good enough or I have a problem with the solenoid. But, do solenoids have ‘soft” failures like this or is it a all or nothing type of device. I assume the next step would be to replace the solenoid.

v/r
Wayne C.
83 SC

[Hladun]

The round relays often fail because the pins lose contact. Use a pen knife to spread the pins but be careful not to break them off. Internals (coils and contacts) don't often fail.

[Jerome Ryals]

Also check your ground cables/straps especially from the transmission to the body this is often the solution to the problem that many people think are starter/solenoid issues.

[Superman]

Yes, solenoids fail intermittently at first, then it gets worse. Failures increase with temperature. the solenoid gets dirty on the inside. To disassemble, you would probably need to de-solder one of the contacts.

The good news is that Bosch solenoids are quite available, and are aftermarket replacements. I recently had to do this, and found that the Bosch solenoid price was actually lower than the aftermarket units. It was somewhere around $30. My starter motor, brushes, etc, were fine. New solenoid last summer, no problems since.

[curiousone940]

You might also consider the possibility of the ignition switch contacts going bad as well. Sometimes a little "jiggling" on the key/ignition switch (while attempting to start) will make a difference in "start-no start" ...if this is the case, then you have isolated your problem.

[Porsche_monkey]

Mine failed. Intermitent at first, then it quit completely.

[Superman]

To make sure it was not an ignition switch problem, I connected a test lead to the proper terminal at the starter, and placed a test light on the passenger seat. That way, I could watch the test light as I operated the ignition switch. The test light turned on, and the starter did not operate. Bingo, bad solenoid or starter. And again, the starter itself was fine. Frankly, starters just operate a few seconds at a time, then they get to rest. Alternators are continuous duty. So, starter motors can last a while. Solenoids are the problem at least 80% of the time that starters don't work. And as I say, a new Bosch solenoid is probably just around $30.

Remember also, that the proper technique for getting at the top fastener holding the starter to the bellhousing, is to bear-hug the tranny and reach it from above. Removing a starter is cake once you see how it's done.

Oh and one more, very very important, thing. The FAT red cable is coming directly from the starter, not going through any switch of any kind, and it is UNFUSED. So, it is hot all the time, and capable of carrying massive amperage. So, I strongly suggest you disconnect the negative battery cable before doing anything around the starter.

[curlesw]

Thanks guys...I think I'll change out the solenoid since they are relatively cheap. Doesn't look too bad.

Sup, thanks for the suggestions...some of my pre-reading mentioned the need to disconnect the negative battery cable or you could fry most (or all) of your electronics...that would suck!

v/r
Wayne C.
83 SC

[beepbeep]

I had exactly same problems and it turned out to be faulty ignition switch.

[Superman]

sounds like it would make sense to do the test light thing, to ensure that the problem is the solenoid rather than the ignition switch.

[Gunter]

I would look at the wires to the starter first. Any signs of corrosion? Or being loose? The top fastener is a 10mm? barrel nut. Super is right about bear-hugging the tranny over the top. You have to feel your way around and manipulate the Allen wrench somewhat using a short extension. With the starter out, you can inspect the ring-gear too.