1998 s70 only starts randomly and "overheating"

drummer3008 · Post by **drummer3008** » 10 Mar 2015, 15:28

my non turbo base s 70 has recently had problems starting, it cranks but it doesnt turn over. it only starts when it wants too. ( there is no outside problems causing it not to start. sometimes is starts in the rain sometimes it doesn't. it snowed and froze over but that was about 4 days before this problem started. and it hasn't been hot its only gotten up to about 70 max.) overheating is in quotes because it doesn't really over heat. in the first 30 seconds the temp gauge slow rises all the way up to the red and then goes back to normal operating temp. i do have some mechanical experience. i have never seen any car get hot that fast.
thanks for the help,
jeff
edit: when my car does start and i can drive it there is no loss of power it doesnt lag or sputter. i did notice that my car idles slightly below normal. its normally around 1000rpm and it idles around 900rpm.

Post by **misha** » 10 Mar 2015, 16:46

Temperature needle on insntrument cluster playing up and random non start condition are pointing to a bad ect sensor or it's connector.Could be also a connector from a car's wiring loom side.Check the wires on ect directly and on connector,there are only two wires.Maybe one of them is loosened.

If not...it's time for new ect.Don't buy aftermarket ect unless it is Vernet.They will not work.Oem Volvo is made by Valeo and you can't go wrong with it.While you are there...replace thermostat too with wahler or vernet only.

Post by **scot850** » 11 Mar 2015, 11:44

+1. Misha is saying where I would also go with this. The 'overheating' could be a symptom of a sticky thermostat. My local dealer service foreman says to change every 2 years max. as they are prone to failure. I think that is a little over the top, but if you are in to replace the ECT anyway, changing the thermostat anyway makes a lot of sense.

The poor starting could be the ECT not registering the out-side temp correctly and either under/over fueling the engine. Again these units fail with time, so again if you don't know how old it is it makes sense to change.

Good luck!

Neil.

drummer3008 · Post by **drummer3008** » 13 Mar 2015, 18:37

Guys thank you so much, that was the problem. I love my car but i dont love trying to find parts for it.
Thanks again

Post by **scot850** » 14 Mar 2015, 00:03

Glad Misha was right again! I just agreed with his good diagnosis!

Neil.