Runs hotter than usual, and purge valve clicks a lot?

Post by **rguzz** » 29 Apr 2021, 11:41

Engine temps easily go to 221F on the slightest incline, drops quickly to 199-210, goes up again in traffic, readings by Ultragauge. I set the gauge to alarm at 220 degrees which it frequently does now. This is not typical. There is a whiff of stale coolant smell inside, and I do believe the heater core needs replacing though coolant level doesn't drop. Radiator is maybe 8-9 years old. Heater core old for sure. Heater core losing pressure? Air bubble? Secondly, purge valve appears to click like crazy and my idle surges frequently. Seems like hot weather problems to me. Thoughts? No CEL's present.

Post by **abscate** » 29 Apr 2021, 16:04

220F is perfectly normal and well withing cooling system design. It has been documented here.

Your purge valve will soon be shuffling off its mortal coil, they annouce death by audible click. It could go on for a year though.

Post by **FlyingVolvo** » 29 Apr 2021, 17:56

Agreed with previous post. I also have an Ultragauge and have been monitoring temps through a wide range of conditions for a while now. Even in cooler ambient temps, in stop/go/city traffic it isn't unusual to see 200-220. I believe (at least on my 2000 XC) that it required about ~235ish for the temp needle to begin to move up from stable 3 o'clock position. I have my alarm temp set to 230.

It's pretty easy to access the heater core, also well-documented here and on YouTube. I'd check it out and look for leaks.

Post by **rguzz** » 30 Apr 2021, 06:56

Heater core is next in line, thanks. There is definitely a change in how quickly the operating engine temp fluctuates, though. Level off from an incline drops from 220f to 195f almost immediately, then a few minutes traffic and back up again. For the most part variations between 195-212f even under pretty extreme driving conditions are the norm for me, occasional readings 217f before the fan comes on. If the core no longer can stay pressurized, will that affect op temps?

Post by **Eddystone** » 30 Apr 2021, 18:58

abscate wrote: ↑29 Apr 2021, 16:04 220F is perfectly normal and well withing cooling system design. It has been documented here.

Your purge valve will soon be shuffling off its mortal coil, they annouce death by audible click. It could go on for a year though.

Love the "coil" double meaning here.

Post by **abscate** » 01 May 2021, 02:28

Eddystone wrote: ↑30 Apr 2021, 18:58
abscate wrote: ↑29 Apr 2021, 16:04 220F is perfectly normal and well withing cooling system design. It has been documented here.

Your purge valve will soon be shuffling off its mortal coil, they annouce death by audible click. It could go on for a year though.
Love the "coil" double meaning here.

I’m trying to do James Joyce proud...

bronco · Post by **bronco** » 02 May 2021, 06:47

mine runs a little hot in the same way . I wanted to put a cooler thermostat in to see if it would help but the back torx bolt is stripped so the whole housing will need to come off the block and I shelved that project until i had something else to do in that area

Post by **FlyingVolvo** » 02 May 2021, 08:33

In many cases in city traffic and/or with the AC on (even on freeway with AC), your coolant will always be hotter than the thermostat's temperature. I would say the thermostat is more important in keeping the engine up to the right temperature from cold, as opposed to keeping it cool. I've had different temp t-stats over the years, and in city traffic and highway with weight/AC/load, my temps will always go up to around 210-220 (higher than both 87 degree t-stat or, 90, or so on).

The only time I really ever see the coolant temp at the t-stat design is on the highway with relatively low load, especially in colder ambient temps.

Post by **rguzz** » 03 May 2021, 21:20

Purge valve replaced with salvage yard item, no clicking and idle is now fine (bad surge valve acting as vacuum leak?), so I think resolved. Heater core replaced, temps under various driving conditions 185f-220f, fan comes on @ 115-117f temps drop nicely after that, coolant drained and replaced. No more smell, though no obvious leak from HC which was original Volvo. Upper vertical screws, both of them best reached from drivers side. Stuffing my 6'1 frame in the passenger footwell and looking up at that screw was not fun. Tstat is 87 if I recall and newish, so thanks everyone.

Post by **abscate** » 04 May 2021, 04:52

I was stuck at the NY Quebec border line once in the T5 and had the AUTEL in hand, and documented the hot idle cycle of 87C...creep up to 105C in about 10 minutes, fan kicks on, coolant back to 87c

Turbo thermostat 87c
NA thermostat 90C

87c is about 190F
205C is about 221F