courier overheating.

Submitted: Sunday, Aug 13, 2006 at 10:17

ThreadID: 36732 Views:2609 Replies:4 FollowUps:5

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andy qld

My sons 97 petrol 4x4 has overheated a few times once to a split radiator which mean't a full head o/haul, next a slpit hose, a new head. Now overheated again without loss of coolant! The mechanic said it's due to towing his work box trailer which is less than 1/2 ton, I think this is a load of bull. Has anyone got any ideas or a reason?
Andy qld.

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Reply By: Member - Ian W (NSW) - Sunday, Aug 13, 2006 at 10:44

Sunday, Aug 13, 2006 at 10:44

Was the radiator replaced after these debacles? The reason I ask is that I managed to overheat my Bravo/Courier by using an incompatible coolant in the radiator.
Being a smart alec and not knowing exactly what I was doing I drained the cooling system, stuck the hose in and thought I had completely flushed the system, then refilled with a coolant mix that reacted with the remnants of the old. The end result was a gel forming in the radiator and restricting coolant flow. We eventually picked it up when we found the top/header tank to be red hot but the lower part of the cooling fins to be stone cold. Out with the radiator and off to a professional who removed top and bottom tanks and rodded the tubes.

I now spend the bit extra and top up with genuine Mazda coolant and have not had any further problems.

A long shot I Know, but a suggestion that might assist.

Ian

AnswerID: 188745

Follow Up By: andy qld - Sunday, Aug 13, 2006 at 13:52

Sunday, Aug 13, 2006 at 13:52

Thanks Ian,Brand new radiator and coolant.
Andy

FollowupID: 446034

Reply By: 120scruiser (NSW) - Sunday, Aug 13, 2006 at 12:47

Sunday, Aug 13, 2006 at 12:47

There are several reasons for overheating so we need a bit more info.
Does it overheat on the free way, and if so does it cool down when you slow down?
Or is it fine on the free way but overheat around town?
Two totally different scenarios with different reasons.

If it is overheating around town or when sitting idle it is air flow which is the problem, ie inoperative clutch fan or air restriction in the radiator.
But if its overheating on the freeway but cools as you slow down its coolant flow restriction/circulation which is either blocked radiator, faulty water pump, sticky thermostat etc.

Hope this helps
120scruiser

AnswerID: 188760

Follow Up By: andy qld - Sunday, Aug 13, 2006 at 13:57

Sunday, Aug 13, 2006 at 13:57

Thanks 120scruiser.
New Radiator, new thermostat, new water pump, new everything bar fan clutch which I'm leaning to.
Andy

FollowupID: 446035

Follow Up By: 120scruiser (NSW) - Sunday, Aug 13, 2006 at 14:08

Sunday, Aug 13, 2006 at 14:08

If it is the fan clutch it should only overheat during low speed operation of at idle for instance whilst sitting at the lights. Now possibly it could overheat with the trailer on as with the extra load the cooling system is working extra hard.

Some modern vehicles have only enough coolant capacity to just do the job so an extra bit of load or a slight loss of coolant can have detrimental effects on the effectiveness of the cooling system.

Most fan clutches can be repaired. You can remove the screws on the two halves and add silicone to the system. It is important not to put too much in. I usually only fill the circular reservoirs level with the top and then re-install the two halves.

Try this link Fan Clutch Rebuild I know its off a Toyota but they are all very similar.

Give it a go as it is only cheap and you have nothing to lose. Be advised the toyota part number has changed but they should be able to look it up. I don't have the new part number on hand as it is at my workshop. I usually keep the silicone in stock and use it on all vehicles.

Cheers
120scruiser

FollowupID: 446038

Follow Up By: andy qld - Sunday, Aug 13, 2006 at 16:06

Sunday, Aug 13, 2006 at 16:06

Thanks for all your help 120scruiser, I will do that to the fan clutch. The problem has arisen at slower speeds usually going up a hill ( not many here in Hervey Bay) towing his work trailer.
Andy

FollowupID: 446057