Wondering if any of you have run into this before.

Yesterday i changed the oil then did a car swap with my sister while i changed hers. On the 30 mile drive home from work she said the overheat warning light on the dash kept coming on when she accelerated hard and would go off ehen she let off throttle. Car wasnt/isnt overheating on the gauge however. I confirmed this on my drive home.

Fast forward to today. The light started out that way then quickly turned into staying on at all times. Even when car is stone cold. Temp gauge is still mid way. Fans still kick on normally. No coolant in the oil and vice versa.

Only thing thats changed since i made the trip down here to visit family is the oil change and thr seafoam i ran thru the vac tree.

My first thought is faulty temp sensor. Second thought is that its overfilled on coolant, i did top it off before i made the drive and there are a few splashed of dried on coolant on the upper rad hose near the thermostat housing/ect.

It does seem to be down on power a bit, and i cant seem to get over 21.5 mpg now...which leads me to the ect on its way out....there is also a slight occasional idle/boost surge where the needle jumps on the boost gauge then drops back down...i suspect this could be from gunk in the iac after the seafoam and italian tune up i did prior to changing oil.

Anyone have any ideas?

 

There is no overheat warning light.

There is a low coolant light. Check the coolant level ASAP.

 

Level is fine, which is weird...maybe the low coolant sensor is out...was another thought i had...

 

Show a picture of the light.

 

It looks like a radiator with a fan on it. Bottom right corner of the cluster 1-2 spots to left of the CEL. Cant upload pics from my phone to the site, terrible data plan reception. Ill be home ti my pc late tomorrow, planning to head to junkyard and grab a couple of these sensors just in case (ect, low coolant, what have you) to rule out both.

As for the idle surge issue, i'll most likely pull the iac hose and hit the valve with cleaner

 

That light is reporting the coolant tank low level switch.

 

URO surge tank?

 

If you mean the overflow tank then yes. Its an uro tank

 

That's your problem. The URO parts are trash, the sensor is not working. Get an Volvo tank or sensor.

 

Found the problem. Overflow tank was bone dry this morning. Its notthe sensor or uro tank after all.

My upper radiator hose sprung a leak at the hose clamp on the thermostat housing. Now to track down a replacement hose. I knew they were needing done soon, been planning to replace both upper and lower, just havent had the funds free for samco silicone ones...

I hate doing a job twice to get it right once live and learn i suppose

 

The sensor and uro tank ARE the overflow tank. If your fluid is low and you accelerate the fluid moves to the back of the tank and will turn on the light on the dash. Let off and it goes off. You were low on coolant.

 

Understood. Weird thing was, when she pulled in the other night the tank was full when i popped the hood. Same thing yesterday. Car was still hot both times...this morning was bone dry though while cold.

Fixed the issue though at least. New upper rad hose installed and while i was waiting for the car to cool off for that job i slapped in a cone filter that my roommate gave me...no real noticeable difference honestly, seems to breathe a touch easier with the spectre cone filter. Not as much lag off the line. Had to buy a maf adapter and some longer bolts but everything is all off the shelf advance auto stuff. Unbolted the maf from stock airbox, left gasket on the end of it and stuffed it into the rear of the adapter. From there it was a matter of getting a 3" coupler and voila.