Over heating Nissan Primera 1999

maclad, Nov 3, 12:00pm
Is the thermostat in behind the radiator hose? My son is having trouble with over heating and firstly I will replace the thermostat. Need advice though as to what you think the cause is. It over heated quite badly two days ago and is losing water, but I think the water is from the plastic reservoir. Took it out and it is intact no cracks. At the same time the car overheats about 3/4 of the way up the gauge, then he said the needle suddenly drops back again. I have been out looking at it just now and ran motor for about 3 or 4 minutes. Even though it was still comfortably cool to touch everything, there is a lot of pressure in the radiator when I remove cap. It wants to blow a lot of water out. I am assuming the seemingly (excessive pressure) is causing more water to track back to the reserve tank causing it to overflow and the radiator to lose water. I know how to remove caps from hot cars without this happening so it is not inexperience. Also the radiator contents, when opened are foamy as is the reserve tank contents. Hoping it is not a head gasket problem but so far no oil in the water.

therafter1, Nov 3, 12:10pm
Sorry to say it, but yes, foaming suggests head/head gasket issue. Probably caused by a blocked radiator on something like a Primera of that age if the radiator hasn't been either rodded or replaced. There is only one thing that will usually pressurize a cool radiator, combustion gasses.

atom.ant, Nov 3, 12:21pm
The good news is if you want to sell it I will buy it. Or if he wants to keep it I can sell him a good cheap motor. We are both in Tauranga

maclad, Nov 3, 12:22pm
I will tell him but he will suss out problem first.

atom.ant, Nov 3, 12:28pm
As above have said. It's the head gasket. Easier and cheaper to replace the whole motor

therafter1, Nov 3, 12:38pm
The reason the temp suddenly drops back is that the gasses have pushed the coolant out of the head so there is nothing for the sensor to read, so it shows a drop. Many have come a gutser on that one (even a dude in a Ferrari, as he thought the problem was simply there was no coolant in the overflow reservoir, so he tipped his daughters bottle of Mizone drink into it and carried on, result was terminal) , people think that because the temp has dropped on the gauge that the problem is solved, so they keep driving, the result is invariably terminal.

intrade, Nov 3, 12:42pm
it be a goner . next time service it.
the client who had the toyota with engine oil in brake fluid.
i had sold her a nissan with a similar engine and carburettor She had it for 10 years or so almost 400,000+km Told her its time to really pull the plug . think she sold it for a few bux . They can do real high milage if you change coolant oil and filters.
RE6 head will be craked 4-sure

maclad, Nov 3, 12:51pm
My son says that when the engine is hot the car heater blows cold air. It did not over heat on his way home this AM, but tends to when sitting in traffic

intrade, Nov 3, 1:01pm
RE-8 thats because there is air in the heater core

therafter1, Nov 3, 1:27pm
Same reason there's no temp reading from the head sensor lol, cos there aint nuthin there.

msigg, Dec 9, 2:51am
therafter1 is probably correct, prob the head gasket or small crack,sitting in traffic there is no airflow through the blocked radiator probably, or fan is not coming on. Look at atoms offer could be a good deal each way. Yes Intrade is correct too, My son had a 1994 primera which do 280k no problems, sold it for $600. Great motors if looked after/serviced correctly.