Hi everyone, i;m driving a 1994 850 T5. temperature dial on the dash board stays at about 4 o'clock, showing a cold engine. the auxilarry meter which show the temp between 98 - 103 degrees. also, just did a top overhaul last week due to overheating. things which i've replaced are a new thermostat (90 degrees, early this year) and ECT sensor.

is the temp shown on the auxilarry meter correct or is my car still overheating?

btw, i'm from malaysia where the ambience temperature is between 25 degrees (morning) and 36 degrees (afternoon).

thnak you

 

Selamat petang Slickz,

Welcome to the forum!

In general, the temp gauge should stay at 3 O'clock position. An easy thing you can do to verify a cold engine is to set the heater at the hottest setting and see if the air coming out of the vents are really hot. If so, there's nothing to worry about. However, if the air is lukewarm, the engine may still be running cold.

I believe the "AUX Temp Gauge" you have noted refers to the LCD temp gauge, right? If so, it is not reading the engine or coolant temp, it is reading the outside air temp (though it does read hotter than actual ambient air temp, once the engine gets hot). That have nothing to do with engine overheating, so no worry.

If you still suspect unusually cold or hot engine, give us another reply.

Jumpa lagi.


JPN

 

JPN,

selamat pagi and thank you for your reply. i do have another auxiliary gauge which takes the temperature reading just before the thermostat, which is seperate from the dashboard gauge and the lcd ambient temperature gauge. i was stuck in heavy, crawling traffic on the way to work and somehow the temperature (auxiliary gauge) stays at 90 degrees. when the road cleared up, driving at normal speed it shot back up to 100.

so is that normal or something is loose or need replacement. one of the error code points to a faulty a/c pressure sensor. could that be the culprit?

btw, i have removed the a/c heater hose from the a/c system therefore i'm not able to do the heater test and the dashboard temp gauge stays at 4 o'clock no matter what the temperature is, even when overheating with steam coming out from the expansion tank.

 

Hi Slickz,

I see, so it is not the LCD.

In that case, I would trust the AUX gauge rather than the original gauge that is staying at 4 O'clock. Overheat usually occurs at above 110-120 degrees Celsius, so as long as the temp is less than 110-120C, it is not overheating. If you see a sign of OVHT again, pull off the road, keep the engine idling and open the hood, and stop the engine when the temp gauge starts drop a bit. Or, some manuals say you should immediately shut down the engine. I'd like to know why it overheated in the beginning, it may be neglected cooling system servicing (clogged/rusted radiator, neglected coolant, faulty thermostat/radiator cap, inoperative cooling fan, engine knocking due to inferior or incorrect octane rating fuel, etc...).

The temp signal sender unit or the gauge itself may be faulty, if it's not responding.

>one of the error code points to a faulty a/c pressure sensor. could that be the culprit?
I doubt if it has to do with the engine cooling system. But using A/C does put a load on the engine and makes it run hotter. When you see a sign of OVHT, turn off the A/C.

I hope this gives you some ideas. Jumpa lagi.


JPN

 

JPN, thank you for your prompt reply. a few more questions, hopefully it will ease my mind. just did a top overhaul about a week ago so its kinda phobia with high engine temperature now.

"I'd like to know why it overheated in the beginning, it may be neglected cooling system servicing (clogged/rusted radiator, neglected coolant, faulty thermostat/radiator cap, inoperative cooling fan, engine knocking due to inferior or incorrect octane rating fuel, etc...). "
radiator is fine, no rust what so ever, coolant is brand new about one week old, thermostat was changed early or late last year, cooling fan running normal, using RON98 fuel with octane booster

"one of the error code points to a faulty a/c pressure sensor. could that be the culprit?
I doubt if it has to do with the engine cooling system. But using A/C does put a load on the engine and makes it run hotter. When you see a sign of OVHT, turn off the A/C."
temperature remains the same even with a/c off.
somehow the temperature remains at that level even in heavy traffic under the hot midday sun.

"Overheat usually occurs at above 110-120 degrees Celsius, so as long as the temp is less than 110-120C, it is not overheating."
does that means that my car is fine despite the temp gauge is registering such temp reading?

 

Panas ya? It's getting ridiculously hot in Narita, Japan. And I work on the ramp at the airport, I'll probably faint or get heat exhaustion one of these days[&:].

Anyway, when they did the top overhaul, I hope they replaced the head gasket and followed the procedures as to putting everything back together. Did you have it done at a Volvo dealer?

It seems that your cooling system is in optimum condition. Is the coolant level in the expansion reservoir normal? I believe it is, assuming from your descriptions.


CORRECTION: 120C is an OVHT range. Sorry about that. The normal temp should be around 85C-95C+ (103C would still be OK though a bit high, as long as you don't notice any of the following symptoms). In general, you would notice one or more of the following when overheating:

1. Lack of power.
2. Knocking.
3. Steam from the radiator cap/engine compartment.
4. Temp gauge registering in the red line.

If you notice any of these, pull of the road. When they replaced the thermostat, did they use OEM (Vernet or Wahler)? Also, when the engine is cold (overnight is the safest), open the radiator cap and see if the coolant is clean. I would also replace the radiator cap, and if possible, have the original temp gaugerepaired. Additionally, see the front of the A/C condenser/radiator. If it's infested with debris, I would clean it.

Lastly, be sure to maintain the proper engine oil level.

Did this help? If not, I'll once again do a search or other members could give you advice too.


JPN

 

I spent 2 days in Kuala Lumpur in 2004 on my way to Bangalore. KL was pretty cool, but of course I only visited the tourist area, not the real KL. Loved the towers. My employer paid for business class tickets on Malaysian Airlines and 200 dollar hotel in KL so I enjoyed the trip very much!

Bump for Tech. Maybe he has an idea.

 

slickz,

The moderator from another 850 forum is from KL. If you contact him he might check out your car. Here is his profile http://www.volvo-forums.com/index.php?showuser=3464. Hope that helps.

 

It is interesting to see the temp actually drop in traffic and rise after moving. My guess is there is air still in the system. Or there is something limiting flow of coolant.

 

Hi everyone,

found the evasive answer to my engine over heating leading to a top job last nite. some time last year, i had an incident where i left the expansion tank cap unsecured leading to massive lost of coolant. didn't found out about that until 20 minutes of driving. i just topped up with water only and three months ago, when i put in the auxiliary meter, again another coolant lost, twice, situation which again was topped up with water only. compound all of those together with hard driving under the malaysian weather and i got myself a top job costing an arm and a leg.

worthwhile to note though auxiliary the temp reading is located after the engine therefore it will register such reading. as shared by other owners during last night outing.

thank you everyone for your info/advice.

conclusion: engine operating at the right temperature
lesson learned: be mindful of coolant water ratio and always tightened the cap

axelm, did spoke to the bear about this and it seems that i'm the first that faced such situation. do give a tinkle in you are coming to malaysia again

 

Ya,faham.

Glad you've found the cause.

According to Malaysia's average ambient temp, I believe 60:40 (60 being water) coolant mixture would suffice.

As to the cap, there are two versions; factory gray & updated green. The green cap seems to have better reputation, though I never had trouble with the factory gray cap.

As long as you keep the following in mind, as well as the lessons learned, your 850 should be ok:

Signs of OVHT:
1. Lack of power.
2. Knocking.
3. Steam from the radiator cap/engine compartment.
4. Temp gauge registering in the red line.

Come back anytime, should other questions arise in the future.

Jumpa lagi.


JPN