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Post by Zed. on Feb 5, 2019 12:33:32 GMT
stupid question maybe.... why the huge aftermarket rad? In my opinion, road cars & maybe competion carsshould be ok with oe spec rads  slow speed / high rev driving will need more air-coolant contact but spirited speed driving should cool with a good condition standard spec system (especially if ducted correctly to direct air at the cooling element not around - undertray fitted?  ?) interestingly, Japaneese cars have massive coolant-radiators compared to UK & European manufacturers, is this a 'hang-up' from the warmer climate in Japan??? I'm a fan of K.I.S.S (keep it simple stupid) so personal cars (& rallycars) have the minimal needed - smallest radiator that can cool but keep engine at optimum temperature (HOT ~ 90'+ as per thermostat settings, not overcool). also... The idea of the 'coolant reroute' is odd to me, I understand the idea behind it but believe that it's sorta the 'emperor's new clothes' - not quite as needed as everyone says  (not that that is being discussed here  ) anyway, enough waffling  Rich. |
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Post by Zed. on Feb 5, 2019 12:36:00 GMT
extra question...... how is the car running?? if the fueling is not setup properly it could be running rich under load (cold) and weak on tickover (hot) Rich. |
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Post by wannabe on Feb 5, 2019 13:45:58 GMT
extra question...... how is the car running?? if the fueling is not setup properly it could be running rich under load (cold) and weak on tickover (hot) Rich. So rich it cools the coolant down from 90degreesC to cold?? lol |
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Post by wannabe on Feb 5, 2019 13:47:29 GMT
stupid question maybe.... why the huge aftermarket rad? In my opinion, road cars & maybe competion carsshould be ok with oe spec rads slow speed / high rev driving will need more air-coolant contact but spirited speed driving should cool with a good condition standard spec system (especially if ducted correctly to direct air at the cooling element not around - undertray fitted? ?) interestingly, Japaneese cars have massive coolant-radiators compared to UK & European manufacturers, is this a 'hang-up' from the warmer climate in Japan??? I'm a fan of K.I.S.S (keep it simple stupid) so personal cars (& rallycars) have the minimal needed - smallest radiator that can cool but keep engine at optimum temperature (HOT ~ 90'+ as per thermostat settings, not overcool). also... The idea of the 'coolant reroute' is odd to me, I understand the idea behind it but believe that it's sorta the 'emperor's new clothes' - not quite as needed as everyone says (not that that is being discussed here ) anyway, enough waffling Rich. I swapped my standard (blocked) rad for a secondhand Fast5 one and I've had no issues with running temperatures - I reckon most users' experience would be the same! I only swapped because my rad was blocked to the point of overheating when driving at even gentle pace, and it had been cleared / rinsed out before but clearly was past the point of no return (or a lot of faffing with cleaning-out products etc.). Does the rad look like this? lol  |
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Post by wannabe on Feb 5, 2019 13:55:48 GMT
Quick thought - one could block half the radiator off with cardboard or similar, to see if that increases coolant/heater temps, as per the atlex recommended way to do so?  |
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Post by atlex on Feb 5, 2019 14:33:49 GMT
start with a nice bit of cardboard :-)
overcooling eh, tis the season.
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Post by BikeTuna on Feb 5, 2019 14:45:29 GMT
The oversize rad was on there from the previous owner (obviously it's wrong, like everything else he did). I could go back to a standard one but I don't want to spend money if I haven't got to the bottom of something. I'll try the cardboard trick and see how it runs on the way home.
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Post by dadbif on Feb 6, 2019 6:36:47 GMT
Cars in the 50’s/60’s used to come with a roller blind arrangement to block airflow to the radiator in winter, do as Atlex suggests and blank it off with some cardboard, nothing to lose.
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Post by dadbif on Feb 6, 2019 22:07:41 GMT
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Post by atlex on Feb 6, 2019 22:58:15 GMT
classic ^^
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Post by dadbif on Feb 7, 2019 9:07:38 GMT
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Post by Rickster on Feb 7, 2019 9:29:48 GMT
I just dont understand this, MX5s have brilliant heaters - mine gets hot even this time of year in minutes. the heater core is fed from the hottest part of the engine and so heats up well before the thermostat opens so the radiator should make no difference to what is happening inside the car, unless you have a coolant reroute which is only required for boosted cars.
My guess is blocked waterways in the block and head and possibly heater core. IF your original rad was gummed up then it is likely that the whole engine is much the same particularly the small tubes in the heater matrix.
Have you done a full coolant flush? there is some good quality stuff out there that actually works I believe.
Pipes in the engine bay can get hot simply by conduction - it doesnt mean the water is circulating - so you'd get a bit of heat probably but not much
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Post by Rickster on Feb 7, 2019 9:41:38 GMT
Just rereading one of your posts - you were stuck in traffic - heater got hot and then when moving again went cool. points to blockages IMO, whats happening there is the rear of the engine is getting (dangerously)hot - the small amount of circulation + conduction you get is warming up the matrix, once you start moving and get more water flow from the pump - cool water gets to the back of the engine and replaces the hot but (and this is a theory) a blocked matrix resists the flow and the heater matrix doesnt stay hot because you are not getting the conducted heat anymore. Basically your heater is just running from the waterways around cyl 4 and not getting much else!
Also as you say the previous owner was an idiot so probably didnt use decent coolant and topped up with tap water - this causes loads of problems in the system.
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Post by dadbif on Feb 7, 2019 19:46:54 GMT
Or, the water pump is knackered, detached impeller?
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Post by Zed. on Feb 7, 2019 22:00:02 GMT
Or, the water pump is knackered, detached impeller? does happen, can be intermittant drive to the impellor if theres no space for it to fall away (the mazda engine has the waterpump in front of the engine with the impellor near number 1 cylinder wall so it cannot fall away from the shaft?) on engines with a void behind the waterpump the impellor can fall into the abyss so no drive  another possibility is, with a plastic impellor, it can split on the boss that fits on it's driveshaft & spin easy test, drain coolant, remove the waterpump's 'elbow' & insert a screwdriver or long poiking-thing into the pump. then with a spanner, turn the emgine & 'feel' if the impellor snaggs against the pokey-thing? & excuse my spelling  Rich. |
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?)
(not that that is being discussed here 
)
le sigh