K-series running too hot?

[7_Malc]

Calling all K-series guru's… your advice please.

Having spent the weekend blatting round Wales, I have noticed that my 1.8 K-series (standard SS 140bhp) is now running hotter than before the trip began. Previously the water temp was around 88-90 degrees, which would drop slightly when driving at higher speeds (better airflow?). Now the temp gauge reads 90-95 even at higher speeds, and rises to 100 in traffic and when idling. The fan still kicks in when idling (and the car is quiet enough for me to hear it) but I can't be sure its not running the fan all the time… no obvious signs of radiator damage or debris blocking the fins.

When I arrived home last night the car was 'hissing' quietly for some time after engine shut off - like a quiet kettle boiling away at low pressure. I don't recall it doing this before.

My questions are:

1. why would the car no longer gain extra cooling from higher speeds?

2. is the hissing noise a danger sign that needs immediate investigation?

    

 - thanks for any clarification you can provide. I've yet to remove the bonnet since arriving home, and am not sure what to be looking for when I do. 

 

[p.mole1]

The hissing noise will probably be the cap drawing in air as the engine cools down. I would check under the oil filler cap for "mayonnaise" and your header tank for oil just in case. If your car is quite old the head gasket could have failed? The first thing I would check is the thermostat. If your car is running at 90/95 degrees this is not a problem as long as it doesn't get up to 100 degrees. It is quite normal for the temperature to creep up when stationary as long as it's not going above a 100 then you may have a problem.

[Jonathan Kay]

I suggest the following, and then please report back;

1. Coolant level and appearance.
2. Engine oil level and appearance
3. Any signs of coolant anywhere under the bonnet or on the floor?
4. Expansion tank cap: is it it still there and is it tight?
5. Hoses external appearance and wiggle by hand for tightness of joins.
6. Radiator external appearance
7. Fan blades external appearance.

Jonathan
(Crossed with Phil's)

[p.mole1]

As Jonathan advises but check your expansion tank cap carefully, particularly the rubber gasket/ o ring inside the cap and the outside of your expansion tank for evidence of the cap leaking.

[john milner]

When one my original hoses was close to totally failing I noticed a white limescale like residue from the minor spraying that it was doing.

[Bricol]

Cap shouldn't be drawing air in as it cools unless faulty - its a sealed system.  When cold, releasing the cap should illicit a "hiss" as air rushes in.

If you've done around 30,000 miles, look all around the head to block joint for signs of leakage - 30 odd thousand miles seems to be the switch for original Rover head gaskets going - the elastomer around the edge on mine failed in the area of the bit over the alternator.  No failure over the liners, so a simple gasket change once the liner height was checked was all I needed.

Mine has always run below 85C, high revs down an autoroute in middle of summer, being thrashed up an Alpine Pass, or indeed sat in traffic on the commute to work.

Your local garage, if it's been around a while, will know all about K-series gaskets . . .

[7_Malc]

Thanks guys - will get a chance to check over the car in the morning, and feedback then.

[SM25T]

30,000 miles .... believe mine to be original at 99,800

[7_Malc]

Here's the report back - thanks again to you all for the guidance.

1. No sign of leakage on the floor or around the engine. Radiator and fan all appears so be in sound condition.

2. Expansion bottle is empty! Slight white residue on cap…

3. Jubilee Clip holding the small pipe to the expansion bottle had slipped down the pipe and was loose. Pipe still attached, but mostly likely this was the source of the hissing as the coolant boiled away around the loose seal?

4. No sign of mayonnaise under oil filler cap.

5. Oil colour is good. Cold engine, so level not tested properly (plenty on dipstick though).   

 

… I have repositioned and tightened the clip. No movement at the bottle / pipe joint now. Clearly there is an absence of coolant, which will need replacing, but have I missed anything before I begin down that path

 

[SM25T]

Slipped down the hose ! You were lucky that hose didn't blow off the bottle under system pressure .... that would have been spectacular. Suggest you check the position and tightness of all of your hose clamps on a regular basis ... including those you can't get at.

[Roadsport06]

Keep an eye on the coolant. Any sign of loss by that hose? It could be a red herring and you have a loss elsewhere. Getting the car up to temperature while the fan is cycling on and off can make it easier to see a leakage.

[Jonathan Kay]

Clearly there is an absence of coolant, which will need replacing...

That's what I'd do.

Are you familiar with the joys and sorrows of filling and bleeding K-engined Sevens?

Jonathan

[7_Malc]

Not first hand, so this will be another learning curve for me. I have read a few things about the process and will happily undertake further research tonight. Does anyone know of a step-by-step dummies guide for coolant replacement and bleeding?

[Jonathan Kay]

Vast amounts in the archives, but unfortunately no Guide yet TTBOMK. You need to think about:

• Bleed points, including additional bleed T-piece, plastic or metal
• Jacking
• Massaging hoses and feeling for temperature
   
• Additional hole in thermostat.

Jonathan

[Bricol]

Have to say I've not had to jack mine - but I fitted a tee to bleed it between heater and engine.

I swopped to a PRRT a decade or more ago, but even before, had no real grief.  

Gffs Rover head gasket went years ago - garage asked how many miles and commented 35000 ish was the failure moment - my Caterham popped at 32 ish . . .

[CageyH]

White residue on the inside or outside of the cap?

If it is on the outside, replace the cap as well.