200tdi getting hot on motorway

So as title suggests, it gets a bit warm on the motorway. Have towed in summer heavy and didn't have any issues started Sunday night. Got about 3/4 of the way on the dial. Water pump was changed within the last year and the head gasket was done a couple years ago. Doesn't seem to be using any water. Haven't been through any mud recently so rad cant be clogged. REALLY hoping its not the head gasket going again. Just had transmission out to change clutch system.

Cheers

Don't need to go through mud to get a clogged rad. Moths, flies and leaves do a good job of that.

Time for a new radiator ?

Might be time for a new rad but I'll have a good look at it in the morning. From what I recall, it's in ok condition. I'll take a photo if I can and see what you all think.

Start with the cheap stuff first, stat etc
With the 200 even when the rad is virtually falling apart and most of the fins missing it still does the job.
Is the viscous fan still fitted?

Ditto with the above.
Thermostat change first. Then consider a Rad change. I recently changed my Rad. Engine would run at normal temperature when doing normal work, but when worked hard like going through the Atlas mountains it would creep towards the hot. Never actually went into the red. It would also creep towards the red when worked hard on the motorway. New rad has fixed all that. Now it never moves off the same spot on the gauge no matter how hard the engine is worked. I also changed the Heater Matrix at the same time whilst the coolant system was empty. They are not expensive. I thought it might increase the heaters. It hasn't been cold enough to test it yet, but I am hopeful.

If it's the original Rad, it's probably time for a change. The internal baffles can become detatched and block the flow. Might be worth trying to flush it out? Cheap fix if it works. If the head gasket was going, you'd probably see other symptoms.

Hi all update on this, took the rad off and gave it a thorough clean in and out. Lots of dirty fluid came out when flushed and continued to flush until clear. Thought I had solved the problem but it is just as bad, if not a fraction worse! Not sure if related but my MPG has been atrocious recently. Keep in mind it only runs hot on the motorway / high speeds which I only do at weekends. During the week its fairly slow driving between towns. Cheers.

Maybe leave it a few months and enjoy a working heater

D90mitch said:

Hi all update on this, took the rad off and gave it a thorough clean in and out. Lots of dirty fluid came out when flushed and continued to flush until clear. Thought I had solved the problem but it is just as bad, if not a fraction worse! Not sure if related but my MPG has been atrocious recently. Keep in mind it only runs hot on the motorway / high speeds which I only do at weekends. During the week its fairly slow driving between towns. Cheers.

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have you felt rad when engines hot

Still an ongoing problem. Thought the new (second of two new ones) thermostat had solved the problem. However on another motorway run it overheated again. Took thermostat out again. Radiator does not get very warm. Took plug out top can see coolant flowing so pump must be ok. Really don't know what else it can be.

For what it costs put a new rad & heater matrix in.
Mine used to do the same & only on a motorway as well.

What thermostat did you buy?

I only ask as I have had 3 stats in a month, first two were bearmach.
1st Stuck open
2nd opened waaay to early
3rd is genuine waxstat and works perfect.

If you have good coolant flow, the rad is flushed or known to be good and the block/head coolant channel are clear then it's likely the stat.

Have you back flushed the rad etc? Does it have any cold spots? It takes surprisingly little gunk to block parts of the rad

How sure are you its getting too hot?

My gauge sits about three quarters on a good motorway blast

Def 200tdi with new rad and stat

Take the stat out and retry. If it's still running hot it's probably the rad. If it's blocked internally you will still see water moving, but it's not being cooled.

Confirm it's running hot before doing anything mechanical. It maybe an electrical issue. An earth fault

Yeah good point