Overheating

[Ranjan]

My car overheated in London traffic today spewing out its coolant, ambient temp was 28 centigrade; did this happen to anyone else?

Just a bit worried......

Ranjan.

[13Black]

Do you still have those Mishimoto fans on by any chance?

Though, 28'C shouldn't really phase an 8 :/ even with the fans.
It's only 22'C here but I caned it home from work without issue.

I guess make sure any air is burped out of the system (raise the front and run it up) with plenty of coolant in the header tank, and be sure that the fans are working when it gets to about 95'C.

[V8 Power]

Wonder if it needs a good flush out, the coolant system could be full of crud not allowing full flow.

[Ranjan]

The car has just come back from a RR rebuild (100 miles done so far) and I was picking BigPete's brain and he says that the 1200 idle and rich mixture won't have helped but he did seem a bit concerned. Has suggested I give Ben a ring tomorrow to see if there could be another issue.

Ranjan.

[delta0]

I’ve sat in traffic in 37C heat (probably hotter as we were in the sun) in France and not had an issue. I would check the system is holding pressure, water is flowing and the fans turn on at the right temperature. Hope it doesn’t need another rebuild!

[350matt]

was the thermostat replaced in the rebuild?

[13Black]

My idle I have set at 1,100rpm (for oil flow reasons) so I can't see 1,200rpm really bumping up the heat that much - being a full bridge port, it's what it needs to be set at, and plenty of other FBP 8s are happy like it.

Similarly with the mixture, I don't think there's much that can be done to alter that given the spec... as well as other similar builds coping just fine. I'd have every faith in Denton's mapping, personally.

The only FBP 8 I've had in with overheating issues had the aftermarket fans wired up wrong, so they ran backwards
Hopefully something simple like that or a stuck thermostat - it does seem like a coincidence that it's still getting warm which perhaps points to something wrong with the cooling system on the car rather than the engine.

[boosted]

Weak rad cap?

Sent from my SM-N950F using Tapatalk

[Dr. FrankenRex]

Mine idles at 2000 and went for a long old drive yesterday in about 23/24 - not exactly taking it easy and had no issues.

Definitely something up I'd say. Give Ben a call, he'll sort you out I'm sure.

[warpc0il]

Any chance that the coolant tank was overfilled?

The Max mark is only half way up and difficult to see.
The system relies on the air space above for expansion.
If the tank is overfilled then it will spew out the excess, when it gets fully hot.

[13Black]

Yis it will throw it out, but it won't overheat because of it.

It'll just throw out what is surplus to requirements when hot, and then find its happy Full level when it sucks air back in while cooling.

Not that that's the ideal method of setting the level but not as big of a problem as having too little.

[warpc0il]

The question is "Did it actually overheat, or was the header tank overfilled and it just spat out the excess coolant and steam, giving the impression that it overheated?"

I've had this happen to two members that brought their cars to me to investigate "over-heating" and also had a neighbour do exactly the same thing on his Dodge Ram.

Similarly, a poorly fitted filler cap will also spew coolant and steam, as the system reaches normal working temperature.

The engine *could* have overheated but it's best to investigate, even only to eliminate, other reasons why it could have been "spewing out its coolant "

[13Black]

Yeah it's a totally valid question to find out what exactly happened.
Though I would assume Ranjan would know the difference between the two, I'm sure we're about to find out either way.

That said, I would also assume that the car would have had its heat cycle by then and pushed out any excess :/ not that anyone should follow my example, but I like to fill my header tank above F - I don't really care if any gets pushed out, but I do want there to be >sufficient level at all times... and I've never had any steamy moments with the car (no more Nigel / Nurburgring jokes pls).

A known good rad cap is always worth a try.

[Ranjan]

Just like to thank Nick for his astute suggestion that the fans may have been misconnected, he was dead right.
I would never have thought of that buddy so you saved me yet another rebuild; I owe you a pint or two

Drove it back after the fix and no problems whatsoever.

Ranjan.

[warpc0il]

@13Black

[ChrisHolmes]

I wonder if that was also the issue at Mallory Park.

[13Black]

ffs

Though, full disclosure:
When that happened previously, I only had limited time to check over the car and never got round to the fans as it seemed to behave immediately after tinkering with whatever, so we assumed a fix - it was the owner who later found the error and told me about it

Weird how happenstance stuff like that ends up being useful - I'll take the beer though