Ahhh, PCH. I recall taking my car a few times down the coast when I lived in SB. I usually went only as far as Malibu but remember a few jams. The open road was great! Wish I'd snapped some pics for posterity (and to keep up with Rob Marks
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Anyway, I'd say its true that traffic can sometimes cause the temperature to rise -- however if your car is properly maintained, it should be able to handle it. Do pay attention to the gauge though -- it is meant to make you pay attention.
And, if you are thinking of changing fuel filter, its not too difficult. Be sure you have the proper filter and the large rubber canister seal. The seal is not always included, so double check.
If you have no lift: what I do is, with an oil pan under the canister, loosen the bolt. Hold the can, and when its free, some fuel will spill out but into pan. Then carefully fish the can up and out. You will then need to get the rubber seal out of the housing on the car. It may fall right out, or will be wedged in. Comes out easily (Gravity!).
I look closely at the filter and to see if anything is in the can. Usually nothing. Wipe it clean, insert new filter. The tricky part now is getting the new seal to stay in its groove while you line up canister. Gravity again! I use a dab of vaseline on the seal, which buys you a few seconds while you get the can sandwiched on. Then line up and tighten the bolt.
Good luck.