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Performance Specialists Since 1963

Running on the Hot Side? Find out Why!

2019-01-09 - ipd Staff

Disclaimer: Direct from ipd’s Tech Tip archive!  This tech tip contains information from previous publications.  Products mentioned may not be available or the information may not be accurate due to changes in supply, manufacturing, or part number association.  Please contact ipd Customer Support if you have further questions.

Generally speaking, Volvos are equipped with pretty good cooling systems that are able to handle just about any load you'd dare to put upon it. I have used a 240 to tow another 240 on a tow dolly for over 300 miles, which included some pretty steep grades. Granted, it didn't fly right up the hills, but it did keep its cool. If you are noticing the coolant needle creeping beyond the normal operating zone when heavy loads are applied there's probably a reason. Using the AC in 90+° weather, towing, hard driving, or climbing long steep grades etc. can all cause the needle to rise. Normally, you should be able to make adjustments in your speed or engine rpm to keep the temp under control. If not, you may need to upgrade the radiator to a high efficiency version like our HD 3 row model.

Here are the most common culprits that can cause your Volvo to run hot.

Low coolant level or too much anti-freeze:

Locate and repair leak, top off coolant. More than 50% anti-freeze mixture can cause hot running.

Internally clogged radiator cooling tubes:

Have radiator tanks removed by radiator shop for proper tube rodding and then re-soldered back together (if your radiator has metal tanks). Radiator flushing will have little effect on this type of obstruction. Also consider replacing with our HD upgrade.

Reduction of air flow due to the accumulation of road grime on the front surfaces of the AC condenser, radiator and intercooler:

Loosen the upper radiator mounts and tilt the radiator (and intercooler assembly if equipped) back towards the engine so you can see into the back side of the AC condenser. Look for an accumulation of dirt and road grime. Clean with high pressure water and degreaser if necessary to restore AC, intercooler and radiator efficiency.

Faulty thermostat sticking in the closed position or only opening partially:

Remove and test or replace

Faulty coolant reservoir cap:

Test cap for proper relief pressure

Collapsed or kinked radiator hoses:

Inspect and adjust or replace

Missing radiator fan shroud:


Loose water pump belts:

Check and adjust

Failure of the thermostatically controlled engine cooling fan (fan clutch):

Test the fan clutch when it's nice and hot out (above 80°) by starting the car and letting it warm up to operat-ing temperature. Hold the throttle open slightly (about 3000 rpm). Listen to the sound of the airflow, it should increase to a roar in 3-5 minutes. This indicates normal operation. If you continue to hold the throttle at 3000, the fan clutch should begin to cycle on and off. You'll hear the roar for about 1 minute and then it should sub-side for about a minute and then back to a roar and so on.

Too much ignition timing advance:

Check to spec with timing light at idle and at 3500 rpms

Blown cylinder head gasket or warped cylinder head:

Pressure test the cooling system