Water Temperature

[1970EuropaGuy]

I drove my Lotus yesterday for the first time in summer like temperatures here in Western Canada, 30C so about 90F.

The water temperature started climbing, stabilizing at about 120C, far higher than the usual 90C that I normally see. After stopping I had some venting.

The complete system was cleaned and pressure tested about 5,000KM ago right before I purchased the car.

I'm guessing this is too high and I should be troubleshooting or is this a normal Europa temperature range?

[jbcollier]

First check your coolant level and for any leaks.  Fill and bleed as required.

Second check your belts.  Good condition?  Adjusted properly?

Third check your gauge to see if it is accurate. Borrow an infrared temp meter and check the temp at the block by the sensor.

If all of the above is good, then we can properly diagnose any issues with the thermostat and rad fan.

Let the engine cool down.  Start it up and check when the thermostat opens.  If it is a Renault engine, should be around 180°F/80°C.  Just feel the outlet hose for a gush of hot water as the thermostat opens.  Then carefully remove the swirl pot cap and check the flow.  A bit weak at idle is ok-ish as long as it gushes out when you blip the throttle.

Replace the swirl pot cap and let it warm up until the rad fan comes on.  No later than 195.  It should stay on for a while to bring the temp down.

Check to see if the rad fan is blowing in the right direction: through the rad into the wheel well. (Yes, it has been known for it to be blowing the wrong way)

Shut it down and check that the rad fan blade is on correctly.  The concave part of the blade should be scooping air. (Yes it is possible to be turning the fan the wrong way.  It will move air but nowhere near as much.)

Report back what you find.

PS: If the gauge is accurate, retorque your cylinder head and reset the valves.  NEVER let it get that hot again.

[1970EuropaGuy]

Thanks JB

[4129R]

if you are driving along at 50+ kph, then the natural air flow through the nose then through the radiator should cool the car down without the need for the fan.

If you are going slowly or stuck in traffic, then the radiator fan is essential.

When the fan is running, check that hot air is flowing into the right front wheel well, as a test for whether the radiator is blowing or sucking, and to test if the cooling matrix is full of dirt and the radiator fins need careful cleaning.

[1970EuropaGuy]

An update:

I took the car out in slightly cooler weather today (20C) and everything is normal. I think the venting may have beeen due to my swirl pot being too full as I also have an addition catch tank. The steam was some coolant evaporating on the exhaust manifold.

I'm planning on taking a close look at the complete system but pretty much everything is new as of 5,000 km ago. Radiator is spotless, belts are new, hoses new and coolant fresh.

JB, I'll make my way through your check list.

One part of the system that has not been touched possibly for some time is the water pump. Could this be a cause?

[jbcollier]

Generally if the water pump bearings have no play, smooth action and there are no leaks from the hole in the bottom, then it is fine.  Very, very, very, very ocassionally the impeller can be loose on the shaft.  I have seen this once (1) in 35 years of changing hundreds, if not thousands, of water pumps.

To check the pump, release the belt tension and try to rock the water pump pulley side to side and back and forth.  Any play at all and it is time to change it.  Spin the pump.  Are the bearings smooth?  Any roughness and you should change it.  Look under the pump.  There is a vent hole underneath, just back of the pulley.  Any sign of leakage?  A small, dry stain of coolant is probably ok.  If it is moist, time to change it.

[1970EuropaGuy]

Thanks all, as much as I hate the internet this type of communication is very helpful in assessing possible issues.

I think I'm running fine. Everything checks out, perhaps I just overreacted to a situation but... better to do that than ignore it.

I have a thermometer so I'll take a close look next time we have a hot day. In two drives today everything was fine.

[Steve_Lindford]

Sometimes the bonnet can lift at speed - leaking air which should be passing through the radiator. Not an easy one to solve - sometimes there is play in the lock - also I believe the bonnet can flex...

[1970EuropaGuy]

Sometimes the bonnet can lift at speed - leaking air which should be passing through the radiator. Not an easy one to solve - sometimes there is play in the lock - also I believe the bonnet can flex...

I definitely have some bonnet lift. I already adjusted the lock play but it's still noticeable.

I don't have any sealing foam in the area so perhaps that would help. Has anyone tried that?

[BDA]

I have seen where one guy (don't remember who - sorry), put weather stripping rubber on his front and rear trunks. This works really well on the rear because the trunk tray is curved similarly to the boot lid but the front of the front trunk is flat and the bonnet is curved so I elected to keep the ugly foam (it's the original foam!) to seal that better.

Anyway, I would pay attention to how well the front trunk is sealed so you don't loose air to the radiator. You might also fill any holes in the area in front of the front trunk for the same reason, but I don't think that is as important.