"interesting" fuel filter contents, and running warmer after oil change.

Changed the fuel filter at the weekend - first time in a few years (naughty). This was on top of the old one. Pretty much nothing in the bottom. It felt a bit gritty - a mixture of rust particles and a bit of gloop? Anything to worry about? It's a 1985 2.5 N/A, running pretty well. I'm pretty sure the fuel tank is not original, it was on the vehicle when I purchased it four years ago, but it's not too rusty.
In what I'm guessing is not related, the engine is running warmer after the service, with an oil and oil filter change. Honestly - before the oil change I warmed it with a 5 mile jaunt, as usual the gauge came up to just over the 1/4 mark. After the service, it moved up to just below the 1/2 way mark. I didn't touch the cooling system at all. Top and bottom hoses getting hot, but not too hot to keep your hand on. Weird. Any thoughts?

The gunk is nasty, could be bacterial build up.

The coolant hoses should get really hot, when was the last coolant / thermostat change ?

Nothing to worry about IMHO - if the filter change was overdue, probably gunk you've bought over the years! How long was it since you changed the oil?

Well if the second road test was done straight after the service the engine would not be truly cold as it was with the pre service road run.

waldamar said:

Nothing to worry about IMHO - if the filter change was overdue, probably gunk you've bought over the years! How long was it since you changed the oil?

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Oil is changed approx every 4k miles.
I use Millers fuel additive at every fill.

Speckydude said:

The gunk is nasty, could be bacterial build up.

The coolant hoses should get really hot, when was the last coolant / thermostat change ?

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I'm on my 4th thermostat in a couple of years, this is the best one yet for getting the engine up to a decent temperature. Coolant is nice and fresh too.

I wouldn't worry, just keep an eye on it - due you trust your temp. gauge?

ps. the millers is good - pump diesel often isn't - one branch of supermarket had such bad diesel it was killing peoples injector pumps - even old school Merc ones that could run on chip fat! your filter has done its job that's all, good luck

waldamar said:

I wouldn't worry, just keep an eye on it - due you trust your temp. gauge?

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Pretty much, I checked it recently with an infrared thermometer, and it reads correctly. I have given up on supermarket fuel, too many horror stories.