New member- 850 hot start issue - I've tried almost all advice in these threads!

[France850]

Hi I have a Volvo 850 estate, 1997. The engine is the B5252s. 2.5L Petrol, non-turbo.
It won't hot start some of the time. It cranks but won't fire. Cold starts are 100% OK. Occasionally, it hot-starts OK too. But it's let me down in gas stations and outside stores where I've just stopped for a few minutes.
Following online advice here and elsewhere, I have changed the coil, both the crank AND cam sensors, HT leads, rotor, distributor cap, fuel filter, thermostat and fuel-pump relay. This has cost me quite a lot of money and I'm not a rich man.
The problem persists.
The only other thing I can think to change is the coolant-temperature sensor. However, the dashboard needle seems to be working OK.
As I said, the car starts perfectly if I let it cool down. But that takes 2 hours!

Would a new battery be likely to change this problem? I imagine that the good cold starts (even after a week of not driving the car) rule this out. My battery reads 12.3V when the engine is not running. And if the engine cools, this battery fires it up straight away.

Thanks for any advice you may have. I really appreciate your comments.

[abscate]

I think the ECT ( coolant sensor) is a good guess, there are resistance measurements in threads here.
The dashboard gauge is not a good diagnostic for the ECT.

[France850]

Thanks abscate, I really appreciate how quickly you replied. I'll probably go ahead and change the ECT.

[gswede]

This is a classic ECT sensor issue as abscate mentioned. 10 min job to change the sensor, its cheap too

[France850]

Thanks gswede, that's reassuring. I'll post back here once the job's done. I sure appreciate you taking the time!

[polskamafia mjl]

Make sure you get an OEM sensor.

[jreed]

Agreed with the advice above.
A couple of good threads on diagnosing the ECT and replacement options:

https://www.matthewsvolvosite.com/forums ... hp?t=52203

https://www.matthewsvolvosite.com/forums ... hp?t=61920