1998 V70 T5m - How hot is too hot? (coolant)

villagepc · Post by **villagepc** » 17 Jan 2015, 13:05

I hate the OEM temp gauge with a passion.
No codes or CEL.

Radiator tanks were leaking coolant at the crimps, so it was replaced. Coolant temps during this time were 188-212F in what can only be a nearly unpressurized system - obviously not the 20-ish lbs or whatever stock might be. The car was never overheated or run out of coolant.
Temp gauge never went beyond 3 o'clock position. Ever. Not in 2 years. Never moved.

Cooling system now pressurized, waterpump started leaking from the front freeze plug.
Replaced water pump.

Drove car around, coolant reached 220F and stayed there for a bit. Burped the system, added more coolant - temps dropped to 195F.

Drove car 30 miles. Coolant light came on 2x. I stopped. Cooled car, added more coolant (burping top hose) each time. Temps were hovering at 220F.

Arrived at destination - car felt hot. Not explosion hot, but clearly hotter than I anticipated. You volvo guys know that feeling, when somethings "off"...

Purchased new thermostat, green radiator cap and ECT sensor - installed all parts. Yes, the weep hole is toward the front, and the correct temperature.

Flushed system with distilled water ( no other additives) Drained radiator and block, filled with 4 qts straight coolant, 3 quarts(ish) distilled water.

Idled car stationary - temps reached 217, cooling fans kicked in, dropped immediately to 204. Let idle
for 10 mins, coolant spiked to 240 (temp gauge actually moved this time) coolant light came on, and I turned car off.

Drained 1x quart from the radiator. Added 1x quart of water. Checked seals around coolant tank, disconnected the upper hose (to the thermostat) and discovered blockage at the tank nipple. Cleared the blockage and verified that the hose was free flowing from the thermostat cap through the hose, and into the expansion tank.

Idled car with cap off, burped hose checking for bubbles /etc - added 8oz of water, then sealed up.

Idled car for 10 mins. Waited for cooling fans to cycle - low speed fan comes on at 217ish, cools to 203 within seconds.

Said "f" it, drove the car 4 miles, aggressively enough to generate ample boost. Temps went to 220, then fan kicked on, cooled to 200's. Normal cruising, temps varied from 195 - 210. Pulled over at a gas station (temp at 203), idled car for 5 mins, then shut off. Popped hood, checked for any gurgling noises, bubbling, groaning, aching, squealing - nothing. Hoses were hot to the touch, and pressurized. Zero leaks. Car started immediately with no hesitation.
During this entire driving romp, the temp gauge went to 3 o'clock - moved maybe 1/2 tick up, then back down when the fans kicked on.

So. My temperature readings are coming from and ODB ELM bluetooth sensor and a program called Torque. I double checked with a separate app, which gave me the same exact temperatures.
The car runs flawlessly - idles perfectly without a hiccup, solid boost, no misfires, no codes - no white smoke / funky smells.

My basis for coolant temperature comparison is based on the fact that with an underpressurized system - the car ran cooler (188-200) under the same ambient temps, but 2 teeth off in timing on both int / exh. Now that 99 percent of the cooling system has been replaced and the timing is set proper, the car runs "hotter" than before. The temp gauge does work properly.

Am I just being overparanoid now? I really, really, really don't want to put the faith of my motor on that crappy temp gauge on the dash. What I expected to happen with all the replacement parts is the ODB reader giving me numbers in the 190's and maybe low 200's in traffic. Now that I see that the cooling fans don't start up until 215, my logic may be flawed. Oh - and I tested both fan speeds.
My next test will be to check for exh fumes in the coolant and a cyl leakdown test if I continue on my trip down paranoia lane. Maybe change the oil. Add some water wetter to the coolant. Replace the coolant tank deal... /shrug

Ultimately - is what I'm seeing "normal". According to the temp gauge, everything's ok. I think it lies.

villagepc · Post by **villagepc** » 17 Jan 2015, 14:14

16 views and no comments? C'mon.. feel free to chime in and fuel my insanity!

Post by **misha** » 17 Jan 2015, 14:58

I don't see that anything is wrong with your car.

Maybe the other members share my opinion and have nothing to say.

Post by **Ozark Lee** » 17 Jan 2015, 16:35

I'm with MIsha - I don't read any kind of problem in the post, everything sounds normal.

...Lee

Post by **mecheng** » 17 Jan 2015, 16:57

Did you use 50/50 mix?
Was it an OEM pump and ECT?

Otherwise a pressurized system should run cooler

Post by **rspi** » 17 Jan 2015, 20:45

Normal. Fan should turn on at 216 and off at 206. Gauge should stay at 3 O'clock until 240 degrees. If it runs under 225 I wouldn't worry about it.

Post by **rspi** » 17 Jan 2015, 20:45

villagepc · Post by **villagepc** » 17 Jan 2015, 21:01

Great - thanks again for the input. I will take the car out for a longer jaunt tomorrow to see how things suss out.

Waterpump is Aisin. ECT is BWD/Intermotor - not OE Volvo. I do, however have spares from the breakers that test good /etc - but I just stuck the "new" one in and let it rip.

Thanks for the input guys, you're a wealth of useful info

Post by **misha** » 18 Jan 2015, 00:39

Don't ever again....ever....use aftermarket ect sensor.

Since that these ones almost never go bad it's better to use used one than aftermarket.

It can cause problems like....incorrect resistance,incorrect temperature reading,prolonged fan working after the engine is switched off and incorrect temperature reading which is sent to ecu.

villagepc · Post by **villagepc** » 20 Jan 2015, 16:24

Just an update on the car temps.

Drove about 30 miles and average temps were around 195 / 200F @ 60mph, and idling at lights - up to 210. The last few miles I beat on it a little giving it the beans and temps were the same. After driving normally for a few mins, parked and checked under the hood. All is well. No coolant pushed out of the reservoir tank or hissing or any wonkyness. Yay.