Datsun(nissan) sd25 diesel engine problem

Submitted: Monday, Sep 06, 2004 at 17:53
ThreadID: 16068 Views:9858 Replies:7 FollowUps:12
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Hi all
My nephew recently brought a Datsun D/cab 4x4 with an sd25 engine (1983 approx). The problem is that oil is getting into the cooling system, but no water is appearing in the sump/tappet cover. The engine still pulls well, compression is good, so we take the plunge and change the head gasket. The inside looks good, a quality steel rule doesn't reveal any distortion. Put it back together. Still oil appearing in water(sigh). A 2hr run on the highway put about 100mls approx of oil in the top tank of the radiator. The only thing that stood out while the head was off, number 4 cyl, well one of the valves, the face was pitted, all the rest were smooth. My nephew and I would welcome your thoughts
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Reply By: Moz - Monday, Sep 06, 2004 at 21:07

Monday, Sep 06, 2004 at 21:07
G'day Ian,
Did you get the head crack tested?

Moz
AnswerID: 75399

Follow Up By: IanP - Tuesday, Sep 07, 2004 at 07:44

Tuesday, Sep 07, 2004 at 07:44
Hi Moz
No, we were praying that it wouldn't come to that.

Cheers Ian
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FollowupID: 335181

Follow Up By: IanP - Saturday, Sep 11, 2004 at 21:19

Saturday, Sep 11, 2004 at 21:19
Hi moz
captnsnooze hit the mark The manual calls it a "sub cooler". Pump it up with compressed air put it into a bucket of water and a small stream of bubbles come out. Thankyou for your time and comments.

Regards Ian P
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FollowupID: 335881

Reply By: Mudguard - Monday, Sep 06, 2004 at 21:19

Monday, Sep 06, 2004 at 21:19
g,day had one for 13 years check your oil/sub oil cooler located right hand rear of engine its like a small heat exchanger.cheers
AnswerID: 75403

Follow Up By: IanP - Tuesday, Sep 07, 2004 at 07:46

Tuesday, Sep 07, 2004 at 07:46
Hi Mudguard
Yeah, went there first. Pressure tested OK.

Cheers Ian P
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FollowupID: 335183

Follow Up By: IanP - Saturday, Sep 11, 2004 at 21:24

Saturday, Sep 11, 2004 at 21:24
Hi Mudguard
You were right it wasn,t until captnsnooze mention sub cooler again that we began to think that we missed something.
We did the oil cooler but not the sub cooler
Pumped it up with compressed air put it into a bucket of water and a small stream of bubbles come out. Thankyou for your time and comments.

Regards Ian P
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FollowupID: 335883

Reply By: ianmc - Monday, Sep 06, 2004 at 21:22

Monday, Sep 06, 2004 at 21:22
Does it have an oil cooler in the radiator? Maybe thats cracked.
AnswerID: 75404

Follow Up By: IanP - Tuesday, Sep 07, 2004 at 07:49

Tuesday, Sep 07, 2004 at 07:49
Hi ianmc
No signs of any piping going into the radiator, other than water.(lol)
cheers Ian P
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FollowupID: 335184

Follow Up By: IanP - Saturday, Sep 11, 2004 at 21:27

Saturday, Sep 11, 2004 at 21:27
Hi ianmc
captnsnooze hit the mark The manual calls it a "sub cooler". Pump it up with compressed air put it into a bucket of water and a small stream of bubbles come out. Thankyou for your time and comments.

Regards Ian P
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FollowupID: 335884

Reply By: Mudguard - Monday, Sep 06, 2004 at 21:29

Monday, Sep 06, 2004 at 21:29
g,day again just remembered while reading the rest of the forum when you replaced the head gasket did you fit the "o"ring in the gasket???
AnswerID: 75405

Follow Up By: IanP - Tuesday, Sep 07, 2004 at 08:00

Tuesday, Sep 07, 2004 at 08:00
Hi Mudguard
You appear to be very knowledgeable about this type of engine. Yes the "o"ring was fitted, but caused a great deal of debate reguarding which way up? After I removed the old one it came to light that it has a soft side and a firm side. (ie a small metal washer that gives it shape). I don't remember, and nor does the manual indicate, which way is correct.
I inserted it firm side down.

Cheers Ian
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FollowupID: 335191

Reply By: Will - Monday, Sep 06, 2004 at 23:32

Monday, Sep 06, 2004 at 23:32
Is it a manual or auto, if an auto it could be tranny fluid leaking into the radiator via the cooler.
As mentioned in one of the replies the head should be crack tested and machined.
It would be worth having a quick chat to an engine shop just to find out if there is a particular problem with that model.
Also are you sure it is new oil and just not old oil that is being cleaned off the inside of the motor.
Have you given the motor a radiator and oil flush ?
Will
AnswerID: 75435

Follow Up By: IanP - Tuesday, Sep 07, 2004 at 08:02

Tuesday, Sep 07, 2004 at 08:02
Hi Will
Manual, flushed a thousand times and you can't miss diesel engine oil.
Cheers Ian P
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FollowupID: 335192

Follow Up By: IanP - Saturday, Sep 11, 2004 at 21:29

Saturday, Sep 11, 2004 at 21:29
Hi Will
captnsnooze hit the mark The manual calls it a "sub cooler". Pump it up with compressed air put it into a bucket of water and a small stream of bubbles come out. Thankyou for your time and comments.

Regards Ian P
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FollowupID: 335885

Reply By: Member - Dragan T (VIC) - Tuesday, Sep 07, 2004 at 01:17

Tuesday, Sep 07, 2004 at 01:17
Long shot, but if everything else fails! In what condition is the turbo? Maybe it has internal crack so it's mixing it there! If head and block are OK turbo is the only place where water and oil could mix. If it is ENGINE oil that is!
AnswerID: 75444

Follow Up By: IanP - Saturday, Sep 11, 2004 at 21:19

Saturday, Sep 11, 2004 at 21:19
Hi dragant
captnsnooze hit the mark The manual calls it a "sub cooler". Pump it up with compressed air put it into a bucket of water and a small stream of bubbles come out. Thankyou for your time and comments.

Regards Ian P
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FollowupID: 335880

Reply By: IanP - Tuesday, Sep 07, 2004 at 08:04

Tuesday, Sep 07, 2004 at 08:04
Hi Dragan T
My nephew wishes it had a turbo.(lol)

Cheers Ian P
AnswerID: 75459

Follow Up By: captnsnooze - Tuesday, Sep 07, 2004 at 15:01

Tuesday, Sep 07, 2004 at 15:01
gooday Ian P,

I reckon it might be the littel heat exchanger down under the filter. Its actually in two peices joined by a little hose. It gave me no end of trouble leaking into water. Just as an aside your nephew should ensure that the little joiner hose on that cooler is in good shape, I blew my old girl up when the hose split. It is near impossible to avoid spilling oil on that hose and it seems to weather quickly...
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FollowupID: 335294

Follow Up By: IanP - Saturday, Sep 11, 2004 at 21:16

Saturday, Sep 11, 2004 at 21:16
Hi captnsnooze
BINGO! you got it. The manual calls it a "sub cooler". Pump it up with compressed air put it into a bucket of water and a small stream of bubbles come out. Thankyou for your time and comments.

Regards Ian P
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FollowupID: 335879

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